Yamaha DTXpress/DTXplorer/DTXtreme

Lets say Im playing a beat on the ride cymbal and snare. Everything 
sounds even volume level. But when I go back to the HH, the FIRST 
time I hit the snare its triggered at maximum volume but then the 
rest of the hits are proper volume. 

I cant figure out what it is. Even if I hit the snare lightly the 
first time(when going back to HH), its louder than the rest of the 
times I hit it. It dosent happen EVERY time but pretty close. 
Sometimes Ill notice the problem, move to another kit, then back 
again and the problem is gone! Or I wont notice the problem, and move 
from the kit to another kit then back again, and the problem 
resurfaces! I think this is what is happening, tho Im not 100% 
positive. 

Any Ideas?

~thanks~