Episode #5.6 - S5-E6
Continuity mistake: When Lady Mary is competing in the Point-to-Point horse race, she is riding her mount sidesaddle style, wearing a long-skirted riding habit. When she (actually the stunt rider) jumps a hedge, she is now riding astride, with both legs over the horse and using a two-stirrup saddle. Also regular riding breeches (pants) are underneath the long skirt when it flies up a bit. These would never be worn with this type of lady's riding habit.
Episode #5.7 - S5-E7
Revealing mistake: When Tom and Sibbie are on the bridge dropping sticks into the water, they run to the other side and you can see their movement through the bricks.
Episode #6.3 - S6-E3
Factual error: During the wedding the groom and ushers are wearing boutonnieres pinned to their labels. Pinning boutonnieres to your lapel is a very new method. Traditionally the flower goes through the lapel button hole. This would still be a common use for the button hole at the time.
Episode #6.7 - S6-E7
Continuity mistake: When Edith stops by her office Laura's there and she's holding a cigarette, which keeps switching between her left and right hands while the two women talk.
Answer: Word gets around. The staff are gossips amongst themselves, but those loyal to the family know who to keep secrets from and who they can trust to share in the knowledge.
Phixius ★