I don't know if anybody else notices little mistakes in a film or T.V. programme that, for one reason or another, were left in the final edit?.
For example there's a bit in "I, Claudius" that I don't think was meant to be seen.
After Sejanus has come back from visiting Tiberius at Capri, he is talking to Livilla about marrying her daughter Helen, and Livilla has a goblet of wine in her hand. Anyway, she goes to put it down on the table but misses at first, then tries again.
There's another bit when Sejanus is talking to a senator, and just a split second before Castor enters the room, you can see the actor giving Patrick Stewart his cue to turn around.