Hi Long,
I have the exact same issue. Working with Metabox AIO and Oxygen. With post_fields included in the shortcode, conditional logic works fine but as soon as I remove it (or remove "content" and leave "title") it just stops working, displaying the field all the time.
Here's the shortcode used in Oxygen:
[mb_frontend_form id="command-form"]
Here's the code for the conditional logic:
https://pastebin.com/TfabQPQu
And the full code for the custom fields:
https://pastebin.com/eAGrSQBh
Thanks!