This still happens for me too; a new folder every 5 minutes. I never found a solution for this issue. I'm concerned about wasted resources, as the script DLL is locked - meaning something is maintaining an open file and probably using up memory. Also it's a waste of processing and memory as the script is being recompiled every time. I've had to schedule an automatic recycle of my website every night, and go manually clean up these folders every few weeks.
-Walter