Offred is seen arranging her scrabble tile pieces to spell SKIN at the 22:04 time stamp. At 22:38 Offred is then seen placing her scrabble pieces onto the table in a way that could no longer spell SKIN.
When Serena Joy is waiting for her husband in a hallway in a US government building, in a flashback 32 minutes into the episode, there is a huge antique brass mailbox next to her on the wall which very clearly has the Royal Coat of Arms of the United Kingdom, because the series is actually filmed in Canada.
When Serena Joy and Offred are talking in the bedroom and the camera is pointing towards the mirror, Serena Joy moves her hand down in front of the mirror but there is no hand visible in the mirror.
In one of Serena Joy's flashbacks she remembers moments where she was not present.