That looks like the RA drive is stopping completely during whatever cycle is happening. While I dont know electronics, that says to me that the mount doesn't know which way to go because of conflicting commands then overcorrects. ??
Whatever the reason I had very similar issues using all these combinations: guide camera (ToUcam/DMK), GPUSB, imaging camera (SX-H9 via laptop/DSLR with HH remote) on G11 (Gemini) and G8 (Digital Drive). The only way I found to get around the problem was to run the GPUSB to its own USB port on the laptop and not through any hub the guide camera was attached to. I'm aware of others having a similar problem. What are you using to guide with? QHY5? other?
If not that, then is it likely there is something stuck in the worm gear? What is the period of the jump? or can you post an image of the graph showing two consecutive jumps? Are the jumps a regular period or irregular? (long shot at the jump appears too symmetrical, but worth considering)
I also noticed your mxRA is 1000. Does it still overshoot like that if you drop it back down to say 100?