For a directory with quota limit set, if an rmdir is done without prior remove limit on the path, the gfid corresponding to the dir remains in quota.conf.
This causes the quota.conf to grow. Each gfid entry takes 17 bytes (16:gfid, 1:type). So it grows very slowly.
Another issue that stale gfid causes is that it increases ipc calls to quotad during list (one per gfid).
Since very few dirs would have limit set on them, it may be an overkill to handle these during rmdir. Instead we could clean them during quota list operation.