I am not sure about the rest of the seasons but for Season 1, the full stop (.) was part of the episode titles.

I haven't had a chance to check the official archived sources from when the show was airing yet, but from a quick search I did on other sources, it seems they either have all the Seasons 1 to 4 Episode Names ending with a Full Stop (.) or all without, so they don't seem to have a mixture of the 2.

However, it would be best to first confirm with the official source archives from when the show was airing. I will try to get this done some time tomorrow.

In the meantime, here are some of the non-archived sources I was referring to:

Starz, without Full Stop

IMDB, with Full Stop

Fandom Wiki, With Full Stop

Season 1 episodes had on-screen titles with a full stop https://i.postimg.cc/prjg6KwS/Screenshot-2023-05-24-at-10-42-00.jpg

If memory serves, before the recent facelift, Starz website had full stops after the titles, but only for the first three seasons.

Confirmed that Season 1 & Season 2 both had Full Stops at the end of the Episode Names:

Season 1

Season 2

Checking Season 3 & Season 4 in some time.

There doesn't seem to be a proper source for Seasons 3 & 4 (or at least I couldn't find a working one that is close to the episodes' release with Wayback Machine).

Technically, since all Episode Names are a Roman Numeral, and Seasons 1-3 uses the following format: {Roman_Numeral}., then maybe Season 4 can also have the same format.

However, since I was not able to confirm this with an official source, not sure how best to proceed on this. Any feedback regarding this matter would be appreciated.