The Dark Phoenix (2): The Inner Circle - S3-E12
Revealing mistake: When Cyclops uses his optic beam to blast Leland through several walls, the final wall that Leland goes through already has a hole in it. (00:15:40)

The Dark Phoenix (2): The Inner Circle - S3-E12
Continuity mistake: The "X" mark torn into Cyclops' shirt changes size and position a few times. (00:09:50 - 00:11:10)

The Dark Phoenix (2): The Inner Circle - S3-E12
Continuity mistake: When Sebastian Shaw is warning the White Queen not to fail the group, the pitchfork-like pin on his jacket disappears between shots. (00:04:10)
Chosen answer: It says MPO "First Exemplary Printing House" which is a real printing company in Russia founded by Ivan Dmitrievich Sytin in 1889. There seems to be something about "named after..." as well.
Sierra1 ★