I would like to see a usability improvement for the situation described in:
I don’t have a well-thought-out specific suggestion at the moment, but this caused us quite a bit of trouble discovering what’s going on (and then finally stumbling over the post above).
For me this is an indication that not having an email for a group resulting in the reply button not showing leads to a mental dead end for the user.
WRT discoverability, I’d suggest still showing the “reply” buttons but a) showing them as disabled and b) explaining in a tooltip why they are disabled.
Replying to issues is a core feature and not having that available was completely dumbfounding me …