In my case, it was not because my keg was overcarbed at all. It was because inside the keg, the drip tube was bent SLIGHTLY and because of the design of the keg (unlike most of my kegs which have a curved dip tube, this one was perfectly straight going into a trough). So I just rebent it and it turned out fine! I think it was mostly occluded by both sedement (i sometimes put sugar in kegs) and the metal side of the trough.
Also, this problem was completely undetectable when my keg was full of beer (cant see bent tube), leading to two very unfortunate evenings! I disassembled most of the tap system before I realized that it must be the keg itself. I have had it before as well that if the keg is pouring too much foam, the tap may be dirty, or clogged which can be fixed with a good wash or soak.
I ended up transferring the beer to another keg and it worked flawlessly.