Just guessing here, but ...
Transducer is mounted on the left side of the trolling motor shaft ... so maybe the shaft and motorhead are getting in the way of a clear view of your jig at times ?? Also, the Livescope ping is 20deg ... so the closer your jig gets to the transducer, the more chance it has of not being in the ping column.
I'd suggest if you're going to be vertical jigging with a Livescope ... do it "in front" of the transducer, not off to the side of it.