We had a 4 hour race at Imola this weekend and there were 2 issues that occurred to most, if not all of the driver.
1) A 1-2 second freeze every time anyone left the server after a driver swap. This was 100% consistent for everyone.
2) Some cars showed up as the whitest white Porsche GTE, even some LMP2's showed up as this white Porsche GTE. Some user didn't had this issue at all while others saw 50% of the grid as the Porsche.
EDIT: The seconds point is not due to the latest patch, it's been an ongoing issue for quite some time.