Several controls animated themselves when the pointer passed over them. A calendar day grew, a meeting-type tile lifted off the page, the availability slider handle swelled, and the board settings button rotated. Pointing at something is not an action, so none of them should have reacted, and the movement made a dense screen restless to read.
They now change colour and nothing else, instantly. The slider handle still grows while you are actually dragging it, because that is a response to something you did.