I have noticed this happening as well, wasn't a problem previously (but I haven't played in a few months so not sure exactly when it broke)
Before you could make a ramp and fire loads of snitches just fine without any blowing up.
Now even with perfect ramp at almost any angle they seem to hit the terrain, but its pretty random.
Maybe something changed with newton script?
FWIW firing dirtbags seems to be fine, which have a much higher aim point.
There is a small lip on this ramp for some reason, which is very hard to see unless you put the camera flat on the terrain. It was small enough that the dirtbag just flew over it, but the snitch gets pushed along the terrain, so just slams right into it.