Clips only come up with half the sound

I am using:

Adobe Premiere Pro
24.5.0 Build 57

or

Adobe Premiere Pro(Beta)
24.6.0 BETA (Build 47)

Windows 11 Pro Intel(R) Core(TM) i9-14900K 3.20 GHz 64,0 GB 64-Bit-System

I usually import takes in mts format and it usually works well. Since some time each take only has half of its sound (not in level).
The picture "Complete timeline.png" shows, that all takes have a problem but one (read later about that). Picture "Same Take in different formats.png" shows the same take in different formats. One in mts one in mp4 format. Mts misses have of the sound. I have no idea  how to stop that.

Ralf

[title edited by mod]