I faced this problem where I used a new flash trigger and after a couple of good photos, photos started appearing like this https://imgur.com/a/iNw4rkr then the camera stopped working for a while and when it did there were two lines following the f stops. so I tried the old trigger and had the same problem, after a while I realized that the shutter was 1/ 400 and 1/250, and when I slowed it to 1/100, no problem anymore.
Make sure HSS is enabled everywhere — on my setup I have to enable HSS in the camera, on the trigger, and on the flash unit.