In The pilot episode, both Starsky and Hutch jump/fall into a swimming pool. A close-up of Starsky in the water shows him in his blue shirt without his sweater, and his gun in his right hand. But the next cut to him shows him standing up out of the water with his sweater back on, and his gun in his left hand.
Throughout the series the rear-view mirror of Starsky's car is often missing when we see a two-shot of the guys in the car from the front through the windscreen. However in other shots of the car in the same scenes the mirror is almost always clearly in place.
The Ford Gran Torino was an automatic, yet Starsky's car always had the very obvious sound that could only be made by a standard (or stick) shift.
Frequently throughout the series, a criminal will be seen using a revolver with a silencer attached. A silencer is useless on a revolver (except for the Russian Nagant M1895) as the sound of the gunshot will escape through the cylinder gap, the space between the front of the cylinder and the muzzle.
Many times, the intel Huggy gathered was very far-fetched, and no explanation was ever given as to how it was obtained. He simply said "my sources reveal" or the like. Huggy was truly Starsky & Hutch's "Deus-ex-machina".
In the intro for the series (taken from the pilot), both Starsky and Hutch end up in an apartment complex's swimming pool. Pausing the frame about 33 seconds in, one can clearly see three tenants having come out on their balcony to watch the filming. It could be argued that they are characters (extras) having heard the police commotion. However, looking closely, the couple on the top floor, right above Starsky, not only have the lights on and their door to their apartment closed, they are completely comfortable leaning on their railway; all this indicates that they are unafraid for their safety, as one would be if they saw men with guns in their pool. (After all, Starsky & Hutch are undercover and wearing plain clothes, not a uniform.) The woman wearing a white robe, even appears to have her arms up to her face, perhaps taking photographs.
Suspension of disbelief required: after so many times Starsky and Hutch going to visit him to gather intel, in broad daylight, there is no way that Huggy would have been able to procure "the boys" any further info, let alone remain alive: everyone knew they were detectives, as established many times. So, their repeat stopping by Huggy's would have surely outed their informant as just that.