Frank has two mugs in his hand, one black and one white. First he puts down the black mug but after the camera angle changes, we see the white mug already on the table and now he's putting the black mug down.
When Madani enters Arthur's house, the hammer is cocked on her pistol, but as she sweeps the rooms, it isn't.
In the scene when Frank goes to Curtis's house, you see Curtis open the fridge and grab 2 beers. He opens both beers and you can see the caps on both beers have been removed. In the next scene he is heard opening another bottle.
When Curtis is approaching his door with his gun drawn the hammer is down. A 1911 can't fire unless the hammer is cocked. A trained ex-marine would know that.