Originally posted by Charger (Source)
For masterwork items, when you seal and unseal an item you have a chance to either get a 1%, 2% or 3% attribute bonus. This is why ya’ll are seeing differences in the base stats and attributes.
When we were digging into this more, we found that some weapons don’t have a 1% bonus, but instead only do 2% or 3%. We’ve started tracking this as a bug and BHS is looking into it now.