[WeldedHarlequin]

I am on the same team as Imax, and I'm the pneumatics captain.
I encountered this problem with the new SMC dual coil solenoids this year, and if you want to go that route I discovered that the problem significantly lessens (if not dissappears) when you remove the small gasket (there are two, one more flat, one smaller and more rounded). Having only the flatter gasket seemed to help.

I remember last year trying to use the Festo valve and having a lot of problems. I really just don't like it. I ended up going with the Rexroth, and not having any port problems.

My situation may be different, but I was using the Rexroth after the SMC (In Series, to slowly adjust the throw of the actuator). Here's what I did (a little bassackwards):

I had the SMC valve as usual, but EA and EB were ported into P on the Rexroth, and the A from the Rexroth was plugged (Actually achieved by running a piece of tube out of it into a plugged piece of brass T). That's the best way I could manage to control the exhaust.

Hope it helps, but if you have any more questions, just ask.