Try and bear with me on this one. I am quite confused by what exactly the bug is, so enjoy my rambling little summary. Possible bugs italized.

Human assassin starts with 20(20) str. 18(20) int.

Human assassin wears eog rings from prison. Goes from mature (32 years) to middle-aged (48) years. Strength goes from 20(20) to 19(19) (I am also wearing +str items, suggesting max str of 19). Int goes from 18(20) to 19(20).

Cut to later. I remove rings. I am now still middle-aged (32 years old). My strength is now 19(20) and my int 19(20). At the trainer, I am offered the option to train strength, even though before I wore the rings and during I had max strength (20 for mature, 19 for middle-aged).

Err. Still with me? I think my beef is with losing a STR point by wearing +age rings and then taking them off, but remaining middle-aged. However, if I were to remain middle-aged, I don't think I'd be able to bring my str back up to 20, would I?

So.. Thanks and enjoy. Feel free to throw the "Risk you take by wearing +age items" card at me.