Clementine 1.4 rc2 as installed from the offical software repository from Linux Mint 21 XFCE.
I used Clementine to convert some FLACs to MP3. The resulting MP3s sounded dreadful. I had set all quality in Clementine to the maximum. After some investigation I found out all MP3s were converted to a sample-rate of 8 kHz. A sample rate of 44.1 kHz is common in audio. 8 kHz is used for telephone calls. I was unable to find any setting that would have caused this. Maybe I missed something, or maybe it's a bug?