So while I was testing the new engine sounds BlazeWolf1122 had provided me, I noticed that the backup sound was increasing in pitch while reversing. I though it was odd that the sound was pitching up while it shouldn't, like it doesn't irl. So just noticed that and decided put up an issues on fsendventd's advice

Addressed in eb42abc.

Fixed in V18.3.0.

I think blaze messed up somewhere or just forgot that backup sounds existed and forgot to exclude that in the pitch change thing