Ok, I check once more the initial layer thickness.
Could it be that (accidently) leaving the filament of the automatic flow calibration of the previous print cause the hotend to have a wrong height data?
Just to clarify, my issue is not during the initial calibration but - afak - during the very first layers.
Let’s try if I meanwhile can add images:
(Edit, still not possible… → how many posts do I need to have so I can upload images?)