Continuity mistake: When Deadpool is talking to Wolverine's skeleton, in one shot the skeleton's mouth is closed, but in the next shot it is open.
Continuity mistake: During his introduction to the TVA, Wade is engaged in conversation with Mr. Paradox. There's an employee at a drawing table near them. When Wade salutes Cap, the woman changes position as the camera angle reverses.
Continuity mistake: When Deadpool and Wolverine are eating a burrito, Deadpool throws his on the ground a few feet to the right. In the aerial angle the burrito is gone. Then the dog runs towards Deadpool and the burrito is now in front of him. When the dog arrives, the burrito is now closer to Deadpool's foot.
Continuity mistake: During the party, Vanessa's grip on her cup differs between instant cuts.
Continuity mistake: After the gory bus battle, Wolverine's claws are clean in one shot.
Continuity mistake: During the conversation between Mr. Paradox and Wade in front of the MCU screens featuring Captain America, a few times Matthew Macfadyen's motions do not quite match when the camera angle switches. For instance, he leans in twice when Wade salutes Cap, and twice away he bobs when he says he "can be a hero amongst heroes."
Continuity mistake: In the locker room of the car dealership, look at Wade's hands when he emphatically says "F**K No" to his own question. He moves his hands away from Peter's shoulders and then back on him. Reaction shot to Peter laughing, Wade moves his hands again, and you can notice the hand position in the reverse angle does not match this last change.
Continuity mistake: Wade, a car salesman, is in the back seat of the Kia Carnival with a family of potential buyers. He answers a question about a different vehicle with crude language, to which one of the kids chuckles and puts his left hand in front of his mouth. New shot and he switched hands.
Continuity mistake: Deadpool pulls out of Logan's carcass the piece of wood that impaled him. It's an overhead camera angle, with both arms of the adamantium skeleton pointing down. He sniffs and throws away the branch. In the next shot, the skeletal hand is now visible at the bottom of the frame, pointing up and close to his face.
Continuity mistake: In the first scene with Wade in his apartment meeting his friends from the previous movies, pay attention to the little chat he is having with Dopinder the cab driver. Ryan Reynolds is holding his green paper cup at different heights between shots.