An invitation printed in 1847 identifies August 3rd as a Wednesday, but the date that year was a Tuesday.
In the opening credits, Dame May Whitty's name is misspelled as "Dame Mae Whitty."
When Emily enters her brother's sickroom and doesn't completely shut its door, a hand and arm very obviously reach out from outside the room and shuts it.
It is not explained how the very English curate Arthur Bell Nicholls speaks with an Austrian accent.