I know that stuff - but not only Aribeth's stats do that...
Actually it's a really annoying bug that concerns any and all henchmen... iirc it's there since the implementation of the better henchie-inventory interface. Whenever you make a map transition, chances are that the engine dearly screws up their stats, lowering them all to a minimum of 8.
You rarely notice unless you regularly look at the henchman charsheet, still... know that it happens with all henchmen, even in the main campaign - and it happens far more often than you'd feel comfortable with. (something every 5th map transition, I'd wager)
What I couldn't 100% ascertain so far is wether or not only the -displayed- values are screwed, i.e. if the henchie is still strong, but the charsheet lies. Yet, since the charsheet is
very closely tied to the actual values in NWN, I'd
bet that the henchman himself is screwed too.
Fortunately there's an easy (if bothersome) remedy for it. Quicksave and quickload, then the stats will be back to normal in 95% of all cases. Still, it's something that constantly annoys me and another one of the reasons why I always play NWN in "lone wolf" style. --_--
-Zel
