Looks like you fixed the loose spark plug cup problem, I had it happened on my DLE 35 but I've been using my 35 for nearly 3 years by now, my problem was a loose spark plug cup, solved it by installing a worm clamp, didn't modified anything just slid the clamp on and the RF went away, it now feels firm.

https://www.flyinggiants.com/forums/...d.php?t=214670