I wasn't aware of this being a known issue - doesn't happen with Jabo's plugins which are what I usually use.
Wish I'd thought of turning monitor upside down - I'd been standing on my head! doh!
lol. it's even funnier if you know that baffoon (who was it.. some 'emu author'?) who really suggested it on the main page of his website.
jabo's internal geometry takes care of this.. switch to external (DirectX) and see what happens. i guess some plugins don't have their own geometry engines? (or they don't work as well).