This particular jitter curve is a result of the drive + scanning speed combination. Others have had the same jitter pattern appear at 8x when scanning with a 6S drive. Lowering the overall scanning speed to 4x fixed the issue, as did setting the jitter pass to run at 4x or slower. Switching CD-DVD Speed/DiscSpeed versions didn’t seem to help it.
Some other LiteOns do something similar, and require the same “fix”.
The thread for the Jitter Speed setting tool v3 for Nero CD-DVD Speed NEW
It’s one of those items that resides on the CodeGuys website, but is more easily found through the CDF site.