It appears that for many, many, many years, we've apparently been filling our ice trays incorrectly.
According to the Tik Tok user below, the flat spots on ice cube trays are where you're meant to fill in the water, not splashing water everywhere by trying to fill in the holes.
In a video posted in May that just went viral, she holds up an ice tray and instead of moving it side-to-side, she lets the water flow on the flat area of the tray mold filling the holes evenly and without the excess water dripping everywhere.