I’m not aware of who/what created it. I’m a user (and nominally a moderator) of a Discourse forum, not an admin.
However, the behavior is occurring BEFORE the Android OS hands off to the App. So that implies Chrome should not be the culprit.
I would expect this be related to how the app register itself with the OS during the OnCreate part of the code? (I assume there would have to be a registration to allow various actions to be prohibited.) In that registration, I wonder if the developer set it to pass too many parameters? (Like CSS it should only be setting those that are critical and different from the default. All the rest should be inherited from the parent settings.)