Well, of course. Releasing the transcript could seriously impair Trump's ability to conduct diplomacy. And it could become a precedent for a flood of similar demands based on frivolous fauxny accusations. That's why I think the Dems made their demand, expecting Trump to decline, triggering their pre-planned follow-up howls of "Cover-UP!!!"
Pence likely knew all that, and also likely knew the contents of the transcript were innocuous (or was there). He just felt differently, if TWSJ and The Hill's annoymorously sourced claims are actually correct.
IOW, I think the decision was a very close call.