Other mistake: When the Sheriff arrives at the end, his car has Pennsylvania license plates but we have been told that the setting is Virginia.
Other mistake: When propping Jane Doe's head up onto the block, her head tilts back but her eyes stay focused toward the ceiling, not tilting back. (00:26:25)
Suggested correction: She is a supernatural entity, so her body does not necessarily behave as a normal body would. It's just one of the many unexpected things about her.
Revealing mistake: When Austin goes to write the Roman numeral "XVII" on the chalkboard, the erased numerals from a previous take are still visible where he's about to write it. (00:41:36)
Factual error: Tommy states that Jimson Weed is a paralytic, but it is not known to have this property. It is however a powerful hallucinogen and deliriant.
Continuity mistake: When we first see Emma in the hallway outside the morgue, she is wearing pantyhose. When she walks into the morgue, the hose are gone and her legs are bare.