Dispel Magic glitch? (in General)

Something very strange happens when I fight opponents who have Dispel magic: My Dex drops from about 160,000 to about 30,000. I look at my dexterity at the end of the battle and I just don't see why.
My strength is not affected; it remains at about 200,000. I checked to see if they have Ethereal chains at all, but they don't.
I've read and re-read the entry for dispel magic and I don't see anything about it cutting opponents Dexterity. I know of no other abilities that only cut Dex but not Strength.
None of them used an Assassin's Crossbow, either. Could you tell me whats going on here?

There are penalties for using a Ranged weapon in melee combat. In your case, slings have an 80% penalty to DX/PTH I believe so in battles that go into melee you will see lower DX displayed.

It's because you are using a ranged weapon in melee which gives a big penalty to DX. Equip a melee weapon and you will see that your DX remains the same.

Ahh yes, that must be it! It was just a coincidence that most of the people I fought also had dispel magic >.<; Thank you for that awsome quick answer!