Wavelab 11 and mp3 batch conversion BUG

Hello, there is a bug when I use the batch conversion to covert my audio files in mp3 format. The problem is not repetitive but randomly! The mp3 created has a distorted sound and something like a bit distroyer plugin!
when the issue happens, it is enought close the wavelab and restart it and the problem disappears!

What WaveLab version? What OS? What encoding options?

Wavelab 11.0.30, windows 10 pro, lame and Fraunhofer. I noticed this bug also with Wavelab 10

In the batch processor, when transforming audio to mp3, try to use a single core in the batch options. Especially if you use Lame.

yes I can try, but in this way I lose the option of convert more files simultaneously!

Are you processing hundreds of files? Else this should be rather fast anyway.
Try independently for Fraunhofer and Lame. I think Lame could be more subject to the problem you report.