I have found a little but annoying bug in the firmware while doing calibration:
See video first: https://photos.app.goo.gl/LSJPnoGJPTQmiGEq9
If you switch to the other head while the current head is not parked, even if the current one is moved to the parking position, the printer will take the latest position of the previously used head into account and won’t let the newly selected head move beyond that position.