Same experience here. I centered the shaft as best I could during assembly but it slipped to one side after 240 hours of printing. The part is about 4mm too short.
The motors act like generators when you manually move axes and can feed power back into the lcd, causing flicker. Move slowly to avoid this.
+1 for Paul’s technique. This step goes a lot easier if you upgrade to torx screws. One US source is albanycountyfasteners.com.