please help! weird shadow/trail effect how to remove (with image)

when i move the camera there is this weird shadow trail thing that shows up for few seconds and fades out dont know how to remove please help

That’s an artifact from temporal AA. It’s the first thing I turn off in all my projects because of this problem with it. If you don’t already have a Post Process Volume, add one, and tick the “Unbound” checkbox so it applies to the whole level. Then under the PPV’s Settings > Misc section, change the AA Method to FXAA.

thank u!!!