We've uncovered an issue with Gutenberg media uploads clashing with the
image_advanced fields that is very similar to what was reported and diagnosed here: https://support.metabox.io/topic/error-with-image-advanced-in-gutenberg/
When uploading media from controls in the sidebar, the next instances of
image_advanced fields on the page have their values removed once an image is selected from another MediaUpload component.
While that previous ticket dealt with Gutenberg media uploads from within the editor, we're seeing the same behavior for media upload controls that exist within a block's "Inspector" sidebar. I've verified that we are testing with the latest MB version which contains the code solution described in that thread.
You can see it in acton in this demo gif:
In this demo, the "Product Images" panel below the editor is created with MetaBox and both the "Lifestyle Thumbnail Image" and "Studio Thumbnail Image" fields are
It seems like the Backbone media collections are not unique for MetaBox and Gutenberg so the 'removed' event is firing when the WordPress media select window is opened.
The sidebar media upload buttons are being added with the standard MediaUpload component
Happy to PM login information to a staging environment or provide any further debug details we can.