legacy issues are writable and should not be
a message from alex:
A usability issue we have right now: It is possible to comment on tickets in legacy/trac, but you shouldn't.
Look for the "Closed (Moved)" part of the ticket, and you can go to the actual ticket that you should be editing/commenting on.
Yes, we are looking at a way to make it impossible to update legacy/trac tickets without some special permissions, to avoid this.
General rule of thumb: If you need to do anything on Gitlab that is not looking at historical content, avoid legacy/trac. If you can't avoid it, it means we need to extract some more data from it and you should contact the Gitlab admins :-)
All the best, Alex.