New to the forum. Hoping someone can shed some light on an issue I'm running into with my router lift. I can set the height I need but once the router is on for a brief time the bit will drop or raise in height. Original lift was a Jet Xacta lift made by Jessum. Thought it was an issue with the lift itself so I purchased a new lift from Woodworkers Supply this weekend. Finished setup this afternoon and the problem is reoccurring with the new lift. Router motor is from a Porter Cable 690 with 1/2" collet. Issue happens with multiple bits. Almost seems as if the router spindle is out of tolerance. Any thoughts?