I got my KE refurbished, and have been using it without any major issues for a couple weeks now. However, at some point in the middle of my last print (which seemed normal up to that point), it started clunking and then making a grinding sound when attempting to move up or down. Investigating further, it seems like the issue is with the connection between the z-axis motor and the lead screw - when the two screws on the coupler cylinder are loose, the lead screws turn smoothly. When the coupler is tightened, however, turning it feels bumpy, and it seems to sometimes not engage the lead screws, leading to jerky, inconsistent motion when the z-motor spins. I tried ensuring the two screws that tighten the coupler were aligned parallel to the flat edge of the motor’s shaft, but this didn’t seem to help. I appreciate any insight, and sorry if i’ve overlooked some obvious resources for figuring this out - i’ve been searching around but haven’t found much yet that’s applicable. Thanks!