I don’t think anyone flags using the button at the bottom, I generally see the one on the OP being used. That one always works on my machine. Also using Brave.
I’ve previously also flagged the post (from the three dots like ~2 weeks ago) as off-topic, does this have anything to do with it? Otherwise I’m not sure what else to add.
Thanks for the report! The issue indeed does seem to relate to having previously Flagged from dots. We’ve filed a ticket to our internal database and we’ll follow up when we have an update for you.