The issue of critical fails on the lu was supposedly fixed:
viewtopic.php?t=4893I'm 0.9 woodworking and 5 stacks of light crystals in, and things are going fine. Knock on wood? Not sure what the critical fail rate is on -5 synthing.
~50-70% lu break rate on mola at 100 fishing. Got one flat shield so far in bycatch gutting, so I'm in not yet in a rush to try out sawfish.
FYI: In retail, the lu could be lost if the synth was interrupted by zoning into town. Not sure if that was ever fixed, but I'm not in the mood to try. I already lost a light cluster this way here. Maybe I will try spamming some cheap fletchings at the end of a boat ride and see what happens. I'm going to assume that Nas will not restore a lu loss if it happens this way.