After the November update with the improved collision physics I’ve noticed an odd issue. Whenever contact is made with another players car playing online, the cars stick together and do not want to come apart. Its as if they are magnetic. The slightest amount of contact usually ends with one players car pulled around onto the front of the other car and being pushed sideways down the track. It takes a good amount of force to get the cars to separate and the player who is unfortunate enough to get stuck to another car is powerless to break free. This happens with collision assist on and off.
Have not experienced this, but I’ve only done leagues.
If on console, have you tried a restart from the system menu?