Looks like rich html editor which gives you to edit your text at forum. Yet codes are not limited in the box of interface so must be a footer.

text icons

Get out of the application, and when you scroll don't go all the way to the end

I don't know how to remove it permanently

he said log out and login again.
maybe if you using android clean cache and passwords etc.

be sure you had the exact mail and password recorded somewhere you trust.