From my experience with these Sony servers (at least in GT6), it seems to be common for two parties for whatever reason to have recurring issues. We used to have 2 guys in the Turtle Racing League that always had issues with each other. It only occurred if they were both in the lobby. We never got it sorted, so i dont know what can be done as it could be anything between how their networks/systems/countries/ISP/whatever works towards the other. It's baffling. It could be how they communicated via the room host; we never knew. It could've been a third party, whose connection seems fine, but is somehow causing a conflict between the other two.
Remember, we are running races across Oceans with these connections; There will be lag, it is unavoidable. Data can only travel so fast; It's an unfortunate reality of GTSport, racing with people from multiple regions; we can try to minimize it (resetting routers prior to logging on, clearing cache, port forwarding, etc...), but it will occur.
I can only suggest we set ground rules to follow when it occurs prior to an official race (time limits to sort it out, how many restarts, do we remove a member from the lobby to ensure it runs smooth, etc...). Otherwise it will ruin the experience for everyone else in the room. Yes, lag sucks. It could be anyone though, we just need to be ready and willing to miss a race if it comes to that and we appear to be the problem.
From my view in the race tonight, I saw both of them, no problem. But at the start, Tieske's car didnt move. It was stuck like a rock sideways across the grid and everyone at the back just ran into the immovable object in the road. I found it quite humerous actually at the time, but if it happened at the start of a real race and ruined my race, i would have felt differently of course. Any of us would.
I dont think i saved my replay or we could see what happened from my viewpoint.