why are parts of frames constantly highlighted?

so when i scrub through my timeline there is almost always something higlighted and the only way to get it unhighlighted is to hover over it fame by frame with my mouse.

its a really big distraction when I'm checking if my animation is correct.It kind of looks like the geometry or symbols are selected ,but they arn't.

I'd click on [deselect all] but its not avaliable.