tkenny-
The battery industry is full of fraud and counterfeits, so the most important question is WHAT BRAND of battery do you have, and did you get it from the same company whose name is on it? Or a third party vendor?
For instance, the folks at Ultrafire rate all their batteries as xx amps, xx volts, but literally every single vendor on ebay and Amazon is selling counterfeit products that are rated slightly differently on both scores. (And sometimes, 30% higher than the greatest amphour capacity that is made by anyone.)
So my first question would be if you were cheated. I've bough "genuine" Motorola cell phone "extended" batteries, only to find that under the hologram and label, was another label--a genuine Motorola NOT extended battery. And by then, the seller is gone.
I've bought radio battery packs that did not fit properly (respected seller says "Oh, just bend your battery contacts, they must be bad". Uh, no, they're fine thank you and that will just break them.)
All sorts of problems.
And unless you buy crap, the "memory effect" is a myth that refuses to go away. Back in the 90's I was talking to a SAFT engineer about that. SAFT owns the NiCad trademark. They said "Memory? No, not unless someone is using really old obsoleted technology, that's just not an issue for brand names any more." NiCd or MiMh.
So, first tell us just what you have. The charger could be "dumb" and the batteries could have cooked. Or there could be a simple manufacturing flaw. But the simplest answer? Is that it could be a 1200mAh battery pack with a lying label. You'd never know without tearing it apart or load testing it.
Or as gewecke said, is your radio SET for rechargables?