The water bottle moves slightly between shots while Jesse is on the yoga ball.
About 20 minutes from the end of the film, the crew gets a call. They board the firetruck and exit the firehouse. Seconds later, they're seen driving by the firehouse they just exited from.
After the female firefighters enter the burning building, they split up. Captain Katsuni starts off with her left hand by her side, but in the next shot it's already holding onto the handrail.
The exterior shot of the firehouse that has "One week later" superimposed over it is exactly the same as the shots seen earlier. The same cars are parked on the right side of the screen. Unlikely they would have been parked there for a whole week.
One of the plots involves Jesse wanting to get her photo published in the sexy firefighters calendar. The movie ends showing Jesse's photo on the May 2010 page, but the bulk of the movie takes place in March 2010 (as per the calendar we've seen throughout the movie). It can't be two months later, as the calendar would need to be published for the following year (2011) for Jesse to get her picture in it.