We might have found something in regard to this issue: The other night we noticed that my co-op partner had left the 'Enable Telemetry' option turned on from where we were capturing some data late last week. While we haven't actually been capturing anything at all since, the reported issues did start to occur around the last time that we were using the telemetry (which, annoyingly, coincided with the 1.07 patch).
Last night, now having turned that option off, we had our first race all week without a single issue (whereas the best we've had all week has been some minor, re-occurring jittering). I also checked the co-op lobby, and that's showing 3/4 bars consistently for both players now, which is much better (although not perfect).
This really needs more than one race to check it isn't a coincidence (which I'll do over the next week), but it's looking like that could be the cause (or at least having a big impact on things). I wouldn't have thought the telemetry should have this sort of impact, but it's also not out of the realm of unreasonable, especially if it's broadcasting a lot of stuff constantly.
I have this issue with my friend when we are playing 2 player, only me and not him which is really annoying. Do you know if the telemetry was the issue in the end? Would be good to know as I would love to see this resolved.
