I used to print with Z-Ultrat with the corresponding profile in the zcode. I checked this more than once.
@Night Shift: Wrong! I don’t use Z-Temp with the printer at work.
@Julia: I was not able to try a new nozzle, because I haven’t one in stock. If the extruder does not go to or hold the temperature it has to, it could also be a cable issue, right!?