Hello together,
I have found the problem for the wrong display of the textures.
It was me! 
I had done a texeldensity check with UV-Zen before saving the file. But didn’t reset the switch to hide the texel density.
In material preview mode it is not visible in the viewport only when rendering with cycles.
So the texeldensity was rendered with the next time I opened the file and my weak brain didn’t think about it.
Problem solution:
- Stay calm.
- Get distance.
- Look at the problem again.
- Trial and Error.
- Sleep on it.
- Ask Blenderartist forum.
- Describe the problem as precisely as possible.
- Do not start from yourself. Gain distance. Change the perspective.
- Stay friendly and above all stay calm. Because from here on others will see your problem.
- Solve the problem.
- Open a beer.
- Describe the solution in the forum.
Lesson learned…
Thank you for your help!
Warm regards Thomas