I captured a video of what I mean: https://gfycat.com/ThunderousDearCaimanlizard
For 1 frame the player in Channel 60 is in the wrong spot (the spot where he spawned). But it doesn't happen every time.
I confirmed the packets are being processed in the correct order and all on the same frame.
It turned out the ExampleCar.SetRB RFC was only setting the Rigidbody Pos & Rot, but the TNAutoCreate.CreateAtPosition RCC was setting the Transform Pos & Rot.
Setting the Transform Pos & Rot in the SetRB RFC seems to fix it. I'm guessing the rigidbody only updates the transform on the FixedUpdate, that would explain why it wouldn't happen sometimes.
TNSyncRigidbody is the same (saw the same behavior with the cubes).
Hope this helps someone!
BTW, I recently switched from Photon to TNet and am very impressed! Server-side persistence wasn't something I thought I needed until I saw it. It feels like a bunch of possibilities opened up