sadly its none of the above.
i tryed changing diffrent settings including going from TAA to FXAA.
habe a closer look. i made a short clip. this trail is fairly long and remains fairly long
https://i.gyazo.com/c9bccc639aaf22f505a113d6872ebcb3.mp4
here you can even see some kind of artefacts
https://i.gyazo.com/0684612ef11d553272b92bb12c7ef280.mp4
and just for the sake of it
https://i.gyazo.com/05e60047161629fd6edee7a581dc5d5a.mp4
here you can see the main problem.
its like the character is some kind of “hot stone” leaving a disturbance in the air