Foamy Beer??

So I am currently having trouble with a beer foaming up and even though I have done some research I can't seem to figure out why. My situation is this. I have a converted mini-fridge kegerator that holds temp about 39-40 degrees. I have two 5' of beer lines (I think 3/16 ID) that run to perlick 425ss faucets. The beer has been on tap now for almost a month at 10 psi. The tricky part is that it poured great for almost two weeks and just recently started foaming up on me. I can't seem to get a quarter glass without the rest foam. The other problem is that the Pale Ale I have on the other side is under the same conditions and is pouring fine. I have been left to conclude that my problem has to either be a blockage in the line or an air leak of some sort. If anyone has any experience with this sort of thing I would love for your expertise. Let me know if you need any more information as well. Thank you

First thing to try is swap the beer lines between the two kegs...

Cheers!