Just want to report back that my dealer Undentia in Sweden and Matrix Audio helped resolve the issues. Today I have received a new Element M as replacement, and I did some quick tests:
1) Display is noticeable brighter than the previous one, no missing pixels and text are displayed sharp as they should.
2) The electrical noise is still there, but I cannot hear it 20cm away from the device. It is a big difference comparing to the previous one.
All in all I'm now a happy owner of Element M. I'd like to help with software issues, and will keep adding to this thread.