Hmm. That is odd. Perhaps this bug was not related to the save problem at all, and my little patch corrected a different issue - one where if one of the actors was detected as having no weapon in either hand at some point, it would try to pull an undefined value from a weapon that didn't exist, rather than an undefined value on a weapon that was simply missing the required value in the first place.
In either case, I suppose the patch fixed it. Do let me know if you notice any other weird crashes like that one.