It's unclear how exactly the two are going to interact, but it makes sense that General Leia, Poe's boss in the Resistance, would be a little stressed. Sure, they were able to destroy Starkiller Base at the end of The Force Awakens, but not before the First Order demolished an entire New Republic system. That, plus Han Solo is dead and Leia's child, Ben, is still pretty evil as Kylo Ren.
So, if she's a little worked up while demanding results from her flying ace, we couldn't be all that surprised. These are stressful times. However, if Leia's stressed, Fisher wasn't while they were filming.
"At every moment she would just wander over with her Coke — she was constantly drinking Coca-Cola — and find a way to undercut the situation or to cut through something to make me laugh," Isaac told Business Insider.