Sorry about the long rationale, I noticed it had been suggested ~5 times and there wasnāt a specific statement that defined voltage within the book in the way this card desires to.
Yeah, this is an issue that has come up more than once. Different resources phase it differently and itās been a while since Iāve dug into the specifics of phrasing for each resource, though UWorld phrases it as āThe electric potential difference or voltage V is defined as the change in electric potential energy per unit charge.ā
Even in the suggestion V = U/q, it is per unit charge by definition. Thus weāve largely elected to keep it as-is, as I havenāt yet been convinced that there is a demonstrable necessity to changing an existing card on several thousand users, at least just yet. 
Could we then change the card to āelectric potential energy difference per unit chargeā? I think the main issue here is that the card is saying electric potential difference (āV) per unit charge (q), which would be V/q. Whereas, electric potential energy difference (āU) per unit charge (q) would be better and accurate wording. I think thatās also what UWorld says from the quote.
Yeah, I think there probably is some room for clarity here. Itās always hard when competing resources decide to have what can seem like small, but ultimately not always perfectly reconciliable, differences in phrasing
Sometimes itās an easy fix, sometimes theyāre just outright not compatible
When in doubt, we try to hew closely to a single resourceās phrasing (usually deferring to Kaplan or UWorld, where we can) and then sometimes make a note in the Extra section if sources donāt entirely agree. This may be an example of where that would be helpful, to avoid future confusion