8 – How to debug a possible permission problem when two entity forms that use the same field show different behavior

I'm using Open Social in a Drupal 8, along with the Hashtags module.
The Hashtag module is a text format filter, which converts hashtags like #foo into a link to a term that you create automatically.

The module works very well, and I have tested it in different entities and text fields. There is an exception where it does not work:
Open Social has an online form "Publish creation" in its flow page, which is basically a customized block with a form of entity creation of the custom type "Publish".

However, if I use the standard publication of Drupal Post create / publish / add / publish, then the text filter works correctly. So it probably has to do with some behavior of the online form.

The standard Drupal permissions page looks good, and I'm using user 1.

Any pointers to how to debug this problem are welcome.
See also some additional details on the topic I posted on drupal.org: https://www.drupal.org/project/social/issues/3042879#comment-13037226