Few weeks ago I had some issues with the rear motor and couldn’t figure out what was wrong. I went over a little grass and thereafter my rear motor was making a loud sound due to vibration (I believe). It wouldn’t go past 20 km/h.I switched to dual motor just so I could make it to work on time. When I got home I tightened all the rear bolts and it helped a little but still get the same sound and vibration when starting up.
If I lift the scooter without the rear touching the ground and run the rear motor it runs fine. No vibration at all, however when I stand on it the problem is there.

I continued trying to figure out the issue but no dice, so ordered a new rear motor and tires/tube. Rear motor arrives tomorrow and started to prep to replace it and found what I believe is causing my issues. The wires connecting to the rear motor, specifically the yellow one are burnt and all of the bolts were not screwed tightly in comparison to the front motor. I’m attaching some pics.
Question is based on the images what would cause this? Will replacing the rear motor now fix it or will the controller do this again? For additional info I had always been running with the single rear motor and rarely used DDM.
In the 3rd image attached, I found some redish residue under the box. Not sure if related but just an FYI.

Thanks for any info!