is it just me, or has legendary gems stopped dropping the last few days ?.
playing GR 90+ and they do not drop
Once you have one of each legendary gem (viewable to Urshi) guardians no longer drop them. If you want multiples of the same gem (e.g. for levelling up for Caldesann’s Despair augments) take the gem from your hero’s gear / inventory / stash, place it in the inventory of another hero and run another GR and that gem will drop again.
Alternatively, and more at risk if you get a disconnect, take a gem from your Stash and drop in on the ground in town. Run a GR and that gem will drop again. Drop it on the ground. Repeat until you have a load of the same gems on the ground. Pick them up and put in Stash. Now you have lots of the same gem to upgrade for augments. (I use multiple invigorating gems for this purpose).