Foaming Bourbon Barrel Porter

My bourbon barrel porter is a little over a year old now.  I took some out of my closet, put into a cooler and opened it a couple days later.  One 12oz bottle foamed like crazy, the other two foamed, but it was manageable.  I opened one from the fridge yesterday (it was in there a month or so), and the foam was heavy in the glass, but didn't come busting out of the bottle when I opened it.
Any ideas on the differing foam behaviors?

Looks like you've got some gushers.  Hold a bottle up to the light, tilt it, and look closely at the neck.  I bet you'll see a ring left behind by an infection. 

There have are threads on a couple of other sites about the same problem.  One was traced to an infected fementer.  Another the problem was with the darker grains.  What kind of recipe AG PM or Extract?

If there is no infection and it tastes good, then you bottled before fermentation was done and the yesast spent the year over-carbonating it.