strange "revving sound" distortion added to tracks after export

Hello, I tried turning every track down down-2, exporting single tracks to see if there is any strange effects added and also unistalled three times, and Im still not sure what going on.

here are the complete vocals tracks in colour with seeting pre-rendered

 and here is the mixdown, where the red marker is the first of the very distinct "bike revving" of distortion is my only way of describing. Even more strange after doing a pre-render on all the tracks, this distortion moved to different places than previous exports....also just to add when exporting the instrumentals alone there was no distortion. 

 and here is tracks 1, with basically all the vocals and nothing is distorting....so the distortion is taking place where nothing is (as you can see frompic 1) So does anybody have a solutions? This is my Holiday metal album lol