1. Go to your inbox
2. Check for new replies
3. Look at the double-checkmark icon in the top-right, get confused over what it does, fear doing something undoable upon accidental tap, so hold your finger over it to try to get a description of what it means
4. No helpful text appears explaining what tapping it will do

The double-checkmark icon is relatively new to me. I've only seen this on Lemmy clients and I didn't remember what it was at first.