My guess is the glitch has to do with too many trades. Such as, once the trade log goes triple digits (behind the scenes, of course, cause Heaven forbid EA let us see a transaction log of any sort) no further trades can be processed
People who only trade once or twice a year never encounter the glitch (this is known as Madden's target audience and why EA sees it low priority)
Hardcore people who trade non-stop to get players and draft picks get it (this is known as EA's "can't give a crap" audience and why it isn't patched yet)
K