I've been testing this out with various storyteller NPCs and I think the pattern of what weapons get nerfed on log out/log in is determined by whether or not the weapon can be typically (or at all) looted off NPCs. I had several -1 cl weapons self-nerf on me, so I'm not sure that's the pattern. It's funny, I have a lightsaber that I grabbed off a Dark Jedi that has no required profession. It and the Ewok crossbow are the only two weapons, besides the wooden staff and reinforced staff, which I didn't bother with looting, that retained the high stats after logging back in after several hours.
Another weapon I looted was a Curved Sword that is categorized as a one handed lightsaber.
Not that I'd be stupid enough to PVP as a non-Jedi profession with a lightsaber lol
It's a shame there are people out there so eager to ruin a good thing.
12 year olds FTW! /sarcasm off
Edited to add forgotten info lol