Imported audio files playback pitch too high in Cubase 8.520

Hey folks, do I have a problem or Cubase (Version 8.520 Pro @ win8)?
Whenever I import audio files into Cubase they are played back with a pitch that sounds too high. Maybe they are played back too fast / with a wrong tempo - I don’t know I’m a Cubase newbie.

My fresh empty project has a samplerate of 44.1 kHz @16 bit. In advance of import I tried to turn on/off the tempo track and/or musical mode or change the tempo manually - without effect on the problem.

The playback problem happens all the time when the imported file is not converted within the import dialogue.
You will say: of course, convert it. BUT:
If the samplerate of the file to be imported is the samplerate as of the project there is no need for conversion - and then the playback is WRONG! ONLY IF THE SAMPLERATES ARE DIFFERENT AND THEN A SAMPLERATE CONVERSION IS DONE, THE PLAYBACK IS OK.
Even if only the bit depth is different and a conversion of the bit depth is done (e.g. from 32 to 16 bit) the playback is wrong.

The audiofiles I have tested are:
wav created by Audacity 44.1 kHz 16bit Stereo
flac created by Freac out of the wav from Audacity
wav created by Samplitude 44.1 kHz 16bit Stereo

Tested with external players playing these files right:

Just to say: Already in the preview of the file-selection-import-dialogue the playback is wrong.
Whats up? Can you help me?

Thanks, Norman.