yea the tilesets seem to cause that problem. one of my LATs on Gileada added a backpal and liek screwed up half my map with that negitized effects. so my number 1 commandment
Thous Shalt Not Use Back Pals
at leats on my server. i even ask tyhm about this problem and he has no idea. maybe goto bomber with this? cuz backpals can add great effects without lighty lag of seteffect.