So I was on the Oval Junkies server, and everytime I was behind a certain racer (gecko) their car at the starting grid just before the green light would do this dance rapidly from left to right side, like it had ants in its pants! To simulate it, hold your hand out, palm down and shake like crazy.

Now that I think about it, I have seen this elsewhere. Any clues?

The sheer acceleration mixed with lag on the BF1 causes very jittery motion with the prediction that the LFS netcode does, also the server may have the packet refresh rate set to 3 or 4, causing that to create more lag also. You also see this to an effect in the FO8, and in some cases but not as likely the GTR cars, because they are more stable under acceleration, whereas BF1 and FO8 are very touchy cars.