The first time Kathy drives to the house, we see the view of her sitting in her car through the windshield. As the camera tracks around to the driver's door, the camera operator is reflected in the windshield near the rear view mirror.
When Behrani and Esmail are talking in Esmail's bedroom, the pillow shifts position from horizontally behind the lower lumbar part of Esmail's back, to standing vertically up to Esmail's shoulders, then back to the original horizontal position behind his back.
The county may have the right to attach property to satisfy a business tax lien, but the process is nothing like in the movie. First, the lien is bought by an investor who is paid interest from repayment of the lien or sale of the property. This usually takes many months or years. If the property is sold, the money remaining after the lien is paid goes to the property owner or estate - it is certainly not kept by the county.
When Esmail turns to face the cops near the end, he has the pistol in his outstretched hands. There is a cut to the cops, then back to Esmail as they shoot him. When they shoot him, the gun is not in his hands, and when he hits the stairs after being shot the gun is already on the ground.