I played this one traning map where when you stepped on this polly it would shoot bounce you up. Is this a bug or a map maker hack?

bug with the mappmaker, when you put ALOT of polys in the same place(over eachother)

can be other thing too...
if the bug ocourrs in a side of a poly, it can be a bug, yes.
my cuising fixed it by compiling the map on the Polyworks, maybe you should try that.

I see this done deliberatly acasionally.