You zaxis might be the trouble. This wasn’t a problem for the last 8 months then all the sudden a lot of issues. So what you are saying is it goes down fine but doesn’t come all the way back up correct? If that is the case below are the most recent solutions found here in the forums.
The last couple were solved byt tking off the anti backlash spring and small nut, or turning up the z axis driver, or making sure your dewalt is not hitting the middle assembly.