Prior to the latest update, at level 29, I was able to desynthesis tonberry lanterns into glass fiber at about a 90+% success rate. Ever since the latest update, out of 9 tonberry lanterns, only 2 were successfully. This rate has been pretty consistent since even though I've higher in alchemy skill since then (32). It also seems (not confirmed for sure) that if I don't HQ the desynth, it's not successful.