Limitation on Dexterity??

So I was checking out "best" fit for the gear I've collected and ran into an oddity I'm not sure about. I have the +8 agility belt on, the level 8 rogue armor (no dex limitations, AC 0, enhanced +5), Power Ring (no dex bonus), those boots with stoneskin and 2 AC Deflection, a cloak with no agility, dragon armor necklace, and two weapons without any agility. So, to recap, ONLY the belt has agility on it. With bonuses for level and feats, I had a 36 agility. I have a Ring of Deft Hands (+4 agility). When placed on, it only gives me 2 dex extra, not 4. I stripped everything off, put JUST the ring on... still +2 to dex. Now either the ring is busted or there's some mechanic not working for the ring. Right now I've shelved the ring because gaining the 1 AC from the 2 dex isn't worth taking the slot up for something else.

Is there a limitation on bonus stats or something? Is there a no more than 10 stat bonus from gear limitation (8 for belt, 4 for ring would be 12 but getting only 10)?

Thanks.

There is a cap on ability "enhancement" bonuses of +12. Be sure you do not have a dexterity Ioun Stone active, as that would explain the issue.

And there it is. Thanks! Yes, I did have a stone on under the thought there was no cap.