When Roy and Johnny are in the water for the cliff rescue at the movie studio they are clearly wearing black Converse Chuck Taylor tennis shoes instead of the fire department-issued leather chukka boots they wore as they entered the water.
Squad 51 responds to a possible drowning in a swimming pool. Both Johnny and Roy jump into the water wearing full uniform and boots. They then arrive at Rampart within one hour of this call and are both completely dry with hair combed & styled. This is not possible.
On each of the first two runs, the man in under the tractor and the drowning, the stock footage of the squad "responding" shows the rig driving without the emergency lights on.
During the cliff rescue at the movie studio, when they go to dump the wagon over the waterfall, the "paralyzed" stuntman swings his legs out of the way.
In the German version (dubbed in 1993) Roy mentions German model Claudia Schiffer, joking on John's problems with the photo shooting. He could have never said that in the original, because in 1972 Claudia was only 2 years old.
At the movie studio, Gage tells Desoto that Dr Bracket authorized an IV of D5W, when they get the victim out of the homemade creek. The next shot shows the firemen loading the victim into a stretcher with an IV already connected.