I've read advice from several professional motor tuners here that the RT motor can screws should be backed out, have some blue loctite applied, and reinstalled and torqued no tighter than just firmly seated. Sounds like there's a slight design issue, hopefully it'll be solved with succesive runs. Hate to see an otherwise well executed motor get a bad wrap for a simple flaw.
Seems to be fixing a lot of mystery RT motor issues.