Chris,
I do have the same problem. The first time I noticed I used contact cleaner on the switches and the footswitch plug-in. Of course, this works for a while.... Then it becomes worse. This means, in my opinion a "machanical" problem. I just exchanged the footswitch plug-in. And because you need to be on the bottom of the PCB, I soldered all points again. I read many forum and this evil will happen at more p1000 users. And between the lines some did the same to solve. I'm now trying to find out if the solutions works. Sometimes it need some hours strumming to reproduce.Do you have experience with connection cabinets? Which specification it may have and so on?
groeten,
Mark