Using the lastest version of the iOS app (0.1.58), I am unable to flag this question for moderator attention:
I haven't tried any others.
When I try and submit my flag, I get the following error:
I was successfully able to flag this question on version 1.60.0
Seems like this has already been fixed, try updating your app.
When you enter the flagging modal, you should see an item at the bottom to do exactly this. Is the problem that it just doesn't work?