@tjlfitzgibbon said:

Season 4:

E13, incorrectly has "(1)" in the title. E14, incorrectly has "(2)" in the title.

These 2 episodes form a 2 parts story, consequently, as per our rules, "(1)" and "(2)" should be added to the titles.

E19, has the wrong episode. Should be, "Double Jeopardy" E20, has the wrong episode. Should be, "Till Death"

E21, is missing. Should be, "Judgment Day" E22, is missing. Should be, "One Minute to Midnight"

The missing episodes are incorrectly in Season 5. That season should only have 18 Episodes, once these two are removed.

We are going as per the original United States broadcast.

Even if the episodes "Double Jeopardy" and "One Minute to Midnight" were produced for season 4, they were originally broadcasted in the United States during the course of season 5, as indicated on this Wikipedia page in the description of these episodes. I quote "(Note that this episode was held over until season 5 in the U.S.)".

You can use this episode group if you want these 2 episodes listed in season 4.

In addition, in Season 5: The episode "Comes a Horsemen" incorrectly has "(1)" in the title. The episode "Revelations 6:8" incorrectly has "(2)" in the title.

These 2 episodes form a 2 parts story, consequently, as per our rules, "(1)" and "(2)" should be added to the titles.

The episode "Archangel" incorrectly has "(1)" in the title. S6E1, incorrectly has "(2)" in the title. S6E2, incorrectly has "(3)" in the title.

These 3 episodes form a 3 parts story, consequently, as per our rules, "(1)", "(2)" and "(3)" should be added to the titles.