When Eladio drives away in the construction foreman's truck, a stunt double can be seen driving it.
Around 00:28:21, we can see the cameraman moving backward on the reflection of the front truck's bumper. On the front/side of the truck's bumper, one frame later, we can see the entire crew.
Around 00:30:05, Flakita takes the police car's door in the nose, then rubs it, but she continues the scene.
When Scully is in the morgue and unzips the body bag containing Maria's body she is not wearing gloves. As both a doctor and an investigator she would know to wear gloves both for protection from any infection agent, and also to preserve evidence and prevent contamination.
When the doctor adds the enzyme to a culture, he states that it is "Puccinia graminis" He mispronounces Puccinia, with a 'ch' sound instead of a 'c' sound. In addition, Puccinia graminis is an obligate parasite of wheat and could never be cultured in a petri dish.
Scully mispronounces the fungus "Aspergillis". She uses a hard 'g' when it should be pronounced "Asperjillis".
In the migrant town, a graffiti "EL CHUPACABRA VIVE" is shown. A native speaker would use the correct Spanish form "chupacabras", not the English form "chupacabra".