Emu XL-7 & MP-7 User's Group

Sometimes when I'm creating a pattern everything is normal. Then, 
after a certain amount of time, every part contains some major 
unintentional effects. For instance, today, I was just messing around 
with it and everything sounded good. Then I left. When I returned, 
everything had this major delay effect. This has also happened in the 
middle of playing a pattern. What could be wrong? Could there be a 
bug, or could it just be settings? Thank you for your help in advance.

I usually only encounter a crash on my MP7 when I clog it up with too 
much MIDI data at one time. (note sticking) I try to do a pattern 
save after each event I change or part I add so I can revert to saved 
pattern if I don't like it. Sort of like an undo function.