One keg is all foam

[Lunkerking]

So I have a Keezer that holds three corny kegs. I just put a new keg in there and I force carb it at 30 for about 24 hours. Then I reduce the pressure to serving and this method always seems to work. However with this particular keg I am getting about 80% foam and lots of spitting. I can see foam in the beer line as well.
I have tried burping the keg and have turned off the pressure but I keep getting this issue. I took apart the posts on the ball lock keg and they seem to be OK. I replaced the ball lock too.

 

[Lunkerking]

I replace the entire outpost with a spare and this seems to work now

 

[Yooper]

I replace the entire outpost with a spare and this seems to work now

That's what I was going to suggest- it sounds like some debris is caught in the poppet or it's not sealing right.

 

[day_trippr]

For "spitting foam" the most common failure mechanism is a damaged O-ring under the Out dip tube flange, which lets CO2 under pressure to be injected right into the beer stream...

Cheers!