When Carter Hall is about to train Kendra Saunders, as they are sending Cisco away, you can see a donkey escaping its enclosure in the background. Moments later, the donkey is back where it belongs.
In order to digitize the Betamax tape, one would need a Betamax player, which is nowhere to be seen when Felicity gets the tape about Vandal Savage.
When Carter and Kendra have a short exchange, it's in Greek but the translation doesn't make proper sense. He asks "Katalavaineis?"="do you understand?" and she answers "Dechomai"="I accept", not "I do". The only context in which that would translate as "I do" is as a response to a marriage proposal, so it's clear it was translated automatically and not by a person. In Greek there's no such response as "I do" in that context, only "yes".