Strangely enough, it’s possible to claim he was in the clear:
(c) Defense.–It shall be a defense that the weapon is possessed and used in conjunction with a lawful supervised school activity or course * or is possessed for other lawful purpose. *
Licensed carry, especially when no school activity is going on nor students present, when en route from a gun range, can be interpreted as “other lawful purpose”.
Now, if the local prosecutors tend to charge any “normal” citizen who possesses a gun under the same circumstances, or if this school board member has called for zero tolerance on gun possession on school grounds, that’s a different story.
But as written, the article doesn’t give enough information to distinguish between hypocritical corruption and a prosecutor intelligently deciding not to waste the court’s time with a Mickey Mouse accusation that is arguably defensible, when no harm was intended, and the whole reason for the law was not even in play.