Ineligible Cover Up

[FGallie22]

Last nights 9th grade game, we had a TE cover up, He went down field. The umpire and I LG, threw a flag for ineligible down field, He didn't touch the pass. The WH, who has been calling for a long time ask us if the TE was cover by a denfer, we both said no, but after the game we ask him why he ask us that ? He said if the TE was cover by a defense back, it would have been offensive pass interference. We have both look all night and couldn't fine anything in the rule book are case book that covers that rule, does anyone no if that is right ?