Wow on Q-22. They can handle high amps. Was Q-23 or r36 toast too? Maybe he plugged a battery in wrong.
Trace may be internal, yes buffer controls FET for K-1, but with everything else working it is either an isolated issue with that segment, or the processor feed.
I have a few boards with motor related issues and usually it traces back to the processor not working right. Wish that was a larger 8 leg chip. G