After each power on, new Core One recalibrates home, bangs the Nextruder against the corner and reports a printer collision  

After each power on, new Core One recalibrates home, bangs the Nextruder against the corner and reports a printer collision

I have assembled a Core One myself. Everything went smooth until I powered-off the Core One after belt tuning and initial calibration. (When I do not use my printer, I completely power the printer off the printer via the main switch on the PSU.)

Now, every time when I power on the printer and start the first print the following things happens:

1. The printer shows the message "Recalibrating home. Printer may vibrate and be noisier".
2. The printer bangs the Nextruder against the front-right corner a dozen times. I understand that this is called "sensor-less homing" and is intentional so that the printer re-calibrates its position after a power-loss. But I read that the printer would at most bang the head against each corner two times, not a dozen times. It really sounds as if the printer is going to break any moment.
3. After a couple of minutes the message "A printer collision has been detected. Homing ..."
4. The printer goes on with banging the Nextruder
5. Eventually, the printer pulls trough, seems to be happy and just prints fine.

What is going on here? I have been really, really carefully during assembly and belt tuning seems fine. When the printer is powered off, I can move the extruder with some but still little force along all axis.

Video with sound: https://storage.googleapis.com/prusa3d-content-prod-14e8-wordpress-forum-prod/2025/09/261b0a77-pxl_20250922_180023082.ts2_.mp4