Just happened today. Appears to have cracked at the 'belly button' point. I've contacted customer support at Andersen hitch. I've also broken many lego blocks.
On a side note, the "belly button" is call the gate, if you want to get technical. (I design plastic injection molds.)
Do the holes go all the way through? If so, they might be better off molding the levelers with blind holes from either side so that you have solid plastic in the center.