Cidery flavor on second keg of a 10 gal batch

Ok, strange question. I brewed up a 10 gal batch of teh Cream of 3 Crops Cream Ale, split them between 2 fermenters, fermented for the same amount of time in the same temp controlled ferm freezer, transferred both to kegs, and set and forget carbed up at ~12 psi at about 40 degrees. The first keg on gas was delicious. The second keg when I tapped it seems to have somehow turned into Apfelwein. And no, I didnt get my kegs mixed up.

I don't think it is Acetaldehyde as the first one tasted fine and both had the same FG (I was lazy and didn't check the OG). The only difference I can tell is that after the 2nd keg was kegged and sealed up, it sat at room temps for a 4-5 weeks and 'conditioned' while the other keg was consumed. WHen I put the second keg on the shelf of my keezer and started carbonating there was still some pressure in the keg so I doubt anything snuck in to infect it, but I cannot determine where the apple/cidery flavor came from.

Thoughts? It is still drinkable, but I really do not need 2 of my 3 taps tasting the same. Should I just pull the keg from the keezer and let it condition for another month while I drink one of the other kegs I have lined up, or just work on finishing it up and calling it a less than stellar keg?

Aww, shucks. No one has anything for me? I guess I will just have to finish it.