Meta Box

...and now it's not working again. I can set it to "Hidden" in, or "Visible" in, and either way it's showing up on every single post in my custom post type. I thought maybe it had to do with conditional logic related to taxonomies, but it looks like conditional logic in general is broken. I set it to only display if true = false, but it is still being displayed.

Thanks Long. I just sent my login details through the form you mentioned.

Conditional Logic seems to be the problem. I can't get any conditions to have an effect on the visibility of a custom meta box.

Yes, I believe the update to AIO v1.13.0 is when the issue began. I do have automatic updates enabled though, so I'm not 100% sure that's when it happened. I'm using the Builder extension, but here's the code it generated:

<?php
add_filter( 'rwmb_meta_boxes', 'your_prefix_function_name' );

function your_prefix_function_name( $meta_boxes ) {
    $prefix = '';

    $meta_boxes[] = [
        'title'      => __( 'Search Engine Optimization Details', 'your-text-domain' ),
        'id'         => 'search-engine-optimization-details',
        'post_types' => ['plugin'],
        'autosave'   => true,
        'visible'    => [
            'when'     => [['_wpo_plugin_category', 'in', 6]],
            'relation' => 'and',
        ],
        'fields'     => [
            [
                'name'    => __( 'Editing', 'your-text-domain' ),
                'id'      => $prefix . '_wpo_seo_editing',
                'type'    => 'checkbox_list',
                'desc'    => __( 'Which settings can be edited through the SEO plugin\'s interface?', 'your-text-domain' ),
                'options' => [
                    'Bulk editing'     => __( 'Bulk editing', 'your-text-domain' ),
                    'Canonical URLs'   => __( 'Canonical URLs', 'your-text-domain' ),
                    'Meta information' => __( 'Meta information', 'your-text-domain' ),
                    'robots.txt'       => __( 'robots.txt', 'your-text-domain' ),
                    '.htaccess'        => __( '.htaccess', 'your-text-domain' ),
                ],
            ],
            [
                'name'    => __( 'Social', 'your-text-domain' ),
                'id'      => $prefix . '_wpo_seo_social',
                'type'    => 'checkbox_list',
                'desc'    => __( 'Which social media structured data is supported?', 'your-text-domain' ),
                'options' => [
                    'Facebook Open Graph' => __( 'Facebook Open Graph', 'your-text-domain' ),
                    'Twitter Card'        => __( 'Twitter Card', 'your-text-domain' ),
                    'Instagram'           => __( 'Instagram', 'your-text-domain' ),
                    'Pinterest'           => __( 'Pinterest', 'your-text-domain' ),
                    'YouTube'             => __( 'YouTube', 'your-text-domain' ),
                    'LinkedIn'            => __( 'LinkedIn', 'your-text-domain' ),
                    'oEmbed'              => __( 'oEmbed', 'your-text-domain' ),
                    'Discord'             => __( 'Discord', 'your-text-domain' ),
                ],
            ],
            [
                'name'    => __( 'Structured Data', 'your-text-domain' ),
                'id'      => $prefix . '_wpo_seo_structured_data',
                'type'    => 'checkbox_list',
                'desc'    => __( 'Which structured data types are supported?', 'your-text-domain' ),
                'options' => [
                    'Dublin Core'            => __( 'Dublin Core', 'your-text-domain' ),
                    'Google Knowledge Graph' => __( 'Google Knowledge Graph', 'your-text-domain' ),
                    'Article'                => __( 'Article', 'your-text-domain' ),
                    'BlogPosting'            => __( 'BlogPosting', 'your-text-domain' ),
                    'Breadcrumbs'            => __( 'Breadcrumbs', 'your-text-domain' ),
                    'Course'                 => __( 'Course', 'your-text-domain' ),
                    'Custom schemas'         => __( 'Custom schemas', 'your-text-domain' ),
                    'Event'                  => __( 'Event', 'your-text-domain' ),
                    'FAQ'                    => __( 'FAQ', 'your-text-domain' ),
                    'HowTo'                  => __( 'HowTo', 'your-text-domain' ),
                    'Job'                    => __( 'Job', 'your-text-domain' ),
                    'Local business'         => __( 'Local business', 'your-text-domain' ),
                    'Logo'                   => __( 'Logo', 'your-text-domain' ),
                    'NewsArticle'            => __( 'NewsArticle', 'your-text-domain' ),
                    'Organization'           => __( 'Organization', 'your-text-domain' ),
                    'Person'                 => __( 'Person', 'your-text-domain' ),
                    'Product'                => __( 'Product', 'your-text-domain' ),
                    'Recipe'                 => __( 'Recipe', 'your-text-domain' ),
                    'Review'                 => __( 'Review', 'your-text-domain' ),
                    'Service'                => __( 'Service', 'your-text-domain' ),
                    'Sitelinks searchbox'    => __( 'Sitelinks searchbox', 'your-text-domain' ),
                    'Software application'   => __( 'Software application', 'your-text-domain' ),
                    'Video'                  => __( 'Video', 'your-text-domain' ),
                ],
            ],
            [
                'name'    => __( 'Automation', 'your-text-domain' ),
                'id'      => $prefix . '_wpo_seo_automation',
                'type'    => 'checkbox_list',
                'desc'    => __( 'Which settings can be automatically generated by the plugin?', 'your-text-domain' ),
                'options' => [
                    'Title'           => __( 'Title', 'your-text-domain' ),
                    'Description'     => __( 'Description', 'your-text-domain' ),
                    'Structured data' => __( 'Structured data', 'your-text-domain' ),
                    'Image alt'       => __( 'Image alt', 'your-text-domain' ),
                    'robots.txt'      => __( 'robots.txt', 'your-text-domain' ),
                    'Open Graph'      => __( 'Open Graph', 'your-text-domain' ),
                    'Twitter Card'    => __( 'Twitter Card', 'your-text-domain' ),
                ],
            ],
            [
                'name'    => __( 'Sitemap Support', 'your-text-domain' ),
                'id'      => $prefix . '_wpo_seo_sitemap_support',
                'type'    => 'checkbox_list',
                'desc'    => __( 'Which types of sitemaps are supported?', 'your-text-domain' ),
                'options' => [
                    'XML'    => __( 'XML', 'your-text-domain' ),
                    'HTML'   => __( 'HTML', 'your-text-domain' ),
                    'Author' => __( 'Author', 'your-text-domain' ),
                    'Image'  => __( 'Image', 'your-text-domain' ),
                    'News'   => __( 'News', 'your-text-domain' ),
                    'Video'  => __( 'Video', 'your-text-domain' ),
                ],
            ],
            [
                'name'    => __( 'Additional Features', 'your-text-domain' ),
                'id'      => $prefix . '_wpo_seo_additional_features',
                'type'    => 'checkbox_list',
                'desc'    => __( 'What other features does this plugin support?', 'your-text-domain' ),
                'options' => [
                    'Content analysis'          => __( 'Content analysis', 'your-text-domain' ),
                    'Data migration'            => __( 'Data migration', 'your-text-domain' ),
                    'Import/export'             => __( 'Import/export', 'your-text-domain' ),
                    'CSV meta import'           => __( 'CSV meta import', 'your-text-domain' ),
                    'Redirect attachment pages' => __( 'Redirect attachment pages', 'your-text-domain' ),
                    'RSS optimization'          => __( 'RSS optimization', 'your-text-domain' ),
                    'Google preview'            => __( 'Google preview', 'your-text-domain' ),
                    'Social previews'           => __( 'Social previews', 'your-text-domain' ),
                ],
            ],
        ],
    ];

    return $meta_boxes;
}

After almost a two year break, I'm trying to figure this out again. In Ahn's initial reply, he said to use "Custom Attributes" in the "Advanced" tab. I've tried to do that, but I think something is wrong. My custom taxonomy is called "Plugin Category" with a slug of "plugin-category". I'm trying to display this meta box any time the "Plugin Category" is set to "Image Optimization" (slug for that term is "image-optimization").

First, I tried this custom attribute:
hidden > ['slug:tax_input[plugin-category]', '!=', 'image-optimization']

Sadly, that hid the meta box everywhere, even if the post was part of the image-optimization plugin category.

Next, I tried these custom attributes (as mentioned here: https://docs.metabox.io/extensions/meta-box-builder/):
tax_query.0.taxonomy > plugin-category
tax_query.0.field > slug
tax_query.0.terms > image-optimization

That didn't seem to have any effect. What am I doing wrong?