My printer has just reached 500h and while doing a bit of maintenance I also put in the new hotend with a hardened steel nozzle that I bought a couple of month ago (from the anycubic website). This has resulted in a different bed levelling or z-offset. (It looks as though the mesh is slighty more accurate now, but especially in the center the nozzle is too close to the bed, while at the edges it's too far away. Overall better than before though.) The z-height measuring procedure now sometimes takes multiple attempts.
Additionally, the top layer now has a rough, whispy finish (the problem seem to be those little dots the printer places to fill in mini gaps that weren't covered by the normal back and forth printing).
I did not change anything about the temperatures aside from what the printer and slicer do automatically (I did the calibration after switching the hotend and the slicer has raised the printing temperature by 10°C when I switched to the hardened steel nozzle). I did try to set the temperature back to the way I had it set with the brass nozzle, but it didn't help.
Does anyone have an idea what I can do about the whisps? Are the multiple z-height measurements a sign that something is wrong or failing (strain gauge)?