The headboard in the bedroom of the trailer has a different carved design when Gina and Nick are using it for their rendezvous than the one shown in the burned out trailer after the explosion.
Santiago and Maria are supposedly living in Mexico, but Santiago's Piper has a US tail number (they start with "N" while Mexican aircraft start with XA or XB)
In the airborne scene of the crop duster dusting the field, the course and actions of the dusting process were inconsistent with real crop dusting. Spraying began at a point well into the field, and no distinct pattern was set such as to avoid missing or re-spraying spots.
Sylvia lives in Portland, but works at a restaurant on the ocean - two hours away.