Plot hole: In 'The Foretelling', it is said that Richard IV reigned for "13 glorious years" with a caption showing 1485-1498. 'The Black Seal' starts on St. Junipers' Day, 1498, but Blackadder spends 12 months locked up with Mad Gerald. So when the Royal Family are finally murdered it is actually 1499.
Plot hole: The ages of the children on the show are really inconsistent. When the show starts in 50 BC, Octavian is around 12, Lucius is an infant and Vorena the Younger is at least 8 (given that she must have been concieved before Vorenus left for Gaul). Three years later Caesarion was born. When Simon Woods takes over the role of Octavian, Octavian is around 19, as stated on the show. Lucius should be seven but looks like he's four and Vorena should be fifteen but still looks eight. Episode 9 of season two takes place in 32 BC, 18 years after the first episode. Octavian might very well be 30, but Lucius (who would be 18) is around seven, Vorena (who would be 26) is a pre-teen and Caesarion (who would be 15) is around eight. Even if the events were moved up so that episode 9 is actually set earlier, the ages of the children still don't match when compared to how much the other characters have aged.
Plot hole: When Takashi is rescued by the other soldiers, he finds a piece of red fabric on him. He then has a flashback to the scene where that same piece of red fabric fell from Hong-pa's body whilst she was hanging beneath the tunnel and realises they are both the same piece. However, when this scene played out earlier, Takashi did not see this happen. He was on top of the bridge and was being held at gunpoint by Eugene, so he couldn't have seen the piece of fabric fall from her body. (00:46:10)
Plot hole: Captain Quinn interrogates a Sergeant and presumably he is let go. Yet for no reason and against all probabilities, Captain Quinn keeps the Sergeant's wallet, which among other things contains the Sergeant's ID card, not to mention other personal effects. How is he going to get on the base without an ID? There is no legal basis for the Captain to keep it. Why keep it? So he could rifle through it and discover a rent receipt later in the show? This is a poor way to further the plot. (00:16:40 - 00:17:30)