One other place this could be a foul, is in your 6 or 8 man codes... In Texas, for 6-man, any time the QB is not under center, he is afforded protection, for both scrimmage kicks and offensive formations. There may be a similar requirement in those rulesets (uncommon as they are).
I don't know anything about NFHS 6 or 8 man codes, but just throwing this out as a possibility.