OL "Check with me" & DL jumping

[OakTree]

Hello, I'm a young official and would like some clarification here. For reference, I'm in Texas calling sub-varsity ball with NCAA rules.

Recently in one of our first games of the season officiating a team which runs a spread, we ran into the increasingly popular scenario where the OL get down into their stance, and upon hearing a coach (or some other mechanism to inform them to 'check with the coach'), the offense turns and checks with the sideline to get an audible or adjustment. The issue I ran into is that eventually the defense jumped when the OL jerked back, making contact. I realize that the OL is allowed to stand up like this, however the coach of the defensive team argued that the OL was in their stance and was popping up in a fairly quick motion that could theoretically resemble the start of a play if a DL were antsy enough to believe it. Is this ever a judgement call, or should this always be a penalty against the defensive team? A couple of more experienced refs on my crew seemed at odds on their assessment of the situation.

Thank you for your time.