Okay, mine now does it when I click enter... If I start a new paragraph, it'll dump the keyboard. So.... Somethings weird. It's not just Samsung, I'm a One Plus 8TFunny enough, it doesn't happen when posting in the thread title box. Every time I hit backspace while posting a message on mobile, my keyboard disappears and I have to tap the cursor to get it back. Real pain in the butt.
Worked fine yesterday but starting having trouble this morning. I am on a Samsung Android phone if it helps.