During the recreation of the "King of the World" scene from Titanic, the boat is supposed to be moving but rarely progresses beyond the Sydney Opera House.
In the airplane scene, the economy class is in a wide body aircraft but the business class is in a narrow body aircraft, when it's supposed to be the same aircraft.
When Ben slams Jonathan's coffee before rushing off to Bea, he places the cup back onto the saucer, but the coffee cup is gone in the next shot. Jonathan is holding only the saucer, then it's back in the wide shot.
At 56:13 when Ben and Margaret are on the boat chatting at the bar, Margaret's glass is half empty and when the camera angle changes it's full.
When Ben and Bea first meet and he's waiting outside the bathroom, she spends several minutes trying to dry the wet spot from her jeans with the hand dryer. The wet spot on her jeans fluctuates between her attempts/positions. This can be particularly noticed when she's hanging off the sink, claiming to have just started a new internship - when her jeans seem completely dry - and a moment later when her jeans are off, being held up to the dryer, and being blown up like a balloon - when the wet spot is freshly fully wet.
When the people on the boat noticed that they had gone overboard, they were told they couldn't turn back because "it was too shallow" even though they had just sailed through that area with no problems, also it's the middle of the harbour which is extremely deep.
The hand prints on the glass cabinet door are not backwards; they were made by Bea's hands flipped outwards when her hands are pressed against the glass.
Claudia mispronounces Martin Scorsese's last name as "skor-SEES-ee" rather than "skor-SESS-ee". She pronounces it differently as to rhyme with breezy.
Bea and Ben meet because Bea says she desperately has to pee and Ben helps her get the key to the coffee shop restroom. She is never shown peeing/preparing to pee. However, it seems as if the actual intent is that the camera only joins her in the washroom after she has finished peeing, she is first shown refastening her pants afterwards. The toilet can be heard flushing as the scene opens.
Having been filmed in Sydney, at the start of the film when Bea is standing on the street outside Ben's place, you can see cars closer to her parked in USA style but one car far up the street is parked in standard Australian style.
When Kat saw Ben on the beach and retied her bathing suit - it was clearly put on upside down. Not sure if that was part of the story and meant to happen.
The sale, possession, and use of fireworks in Australia is strictly regulated and they would not be casually lying around a house as a party novelty.