Z-Axis Test fails after 3.5 upgrade (first layer and printing flawlessly - annoying Test fail reminder  

Z-Axis Test fails after 3.5 upgrade (first layer and printing flawlessly - annoying Test fail reminder

After having updated my 3s+ to 3.5 everything is fine and after some minor adjusting issues it only keeps on constantly failing z-axis test. 
that does not bother me to much as the printer prints perfectly and even MMU3 prints well (after I understood some changes in the way it works now).
I tried quite a lot of changes to get the z-axis test passed. I even went into the secret configuration menu and experimented with different values for z-axis length with no effect (so I got back to default).

In the test the z axis goes up to the top like normal and after the usual ugly noise on the top it starts  going down to 50mm and moving x-axis. Two green x-es for x and y.  After that it goes down to zero with just not touching the build plate (as it should). Than the Extruder goes up some centimeters and gives red x failing to complete the z-axis test.

any ideas what else I could try to get the z-axis test passed?

- I tried test with and without building plate

- I tried with and without nozzle (revo six)

- I flashed the actual firmware again. 

Or is there a way I can switch off the anoying reminder about not finishing all configuration tests. I understand the intention of this message but if the printer works fine and I know there is no error but possible small deviations from factory values,  then I wish I would be able to permanently switch off  this message on printer startup.