warbled when converting to mp3. why?

I have moved over to big sure 11.5.2 and have the current Audacity 3.0.4 and I have an audio project that sounds fine on audacity but when I convert to mp3 320kbps it sounds warbled but if I convert to a wav it sounds fine. This has never happened to me. I had and older version of audacity and did the update and nothing changed. What am i doing wrong or different that has caused this which has never happened before when converting to mp3.

Which MP3 options did you pick?

Screen Shot 2021-08-31 at 16.41.05.png

this is the one I have always done but this is the first time I have done one since I downloaded big sur so no idea.
Screen Shot 2021-08-31 at 8.52.56 PM.jpg

I got it figured out. It was the hz changed on the track so once I took the stuff and put it back to 44100hz it worked perfect like before.

Thank you.