Let me describe this symptom and maybe you guys can give me direction...

Guys, thank you.  Good call on the leak… there was no liquid leaking which I agree is strange.  If the o-ring on the liquid-out post had a nick in it, I agree there should have been beer running down the side of the keg and into the fridge.  I do plan to closely examine the keg and I can check the poppet too.  I have never seen this happen and I have 10 kegs so I feel like something is new here.  I also have to assume it’s the keg since the new beer on that faucet is dispensing properly.  I wondered if there was a kink in the beer line that was making it foam so much but I feel like I have isolated this to the keg itself.