Terrible sound Main Mix Export and Track 11&12 on SD Card

[Peyugo]

Hi, I have a question: When I record a song on my Tascam Model 12, all tracks 1-9 on the SD card sound exactly like the MTR tracks. But 11 and 12 and the Main Mix export sound terrible: thin, without depth, like from an old radio, just horrible. What could be the reason for this, what am I missing? Or is it a defect in the device? I would be very happy if you could help me further