These are recent episodes, with cache being in the game. The value 0.0 was stored when there were no ratings yet.
If you check now, you will see a rating of 7.7 for episode 5.
Episode 6 still has 0.0 - but that's just a matter of time.
Well, I somehow doubt it's (only) a caching problem.
It isn't just related to recent episodes. Take a look at for instance this title, which still says 0.0 on Opensubtitles.
It's been around since 13 October 2017 and uploaded since October 28. Not exactly 'recent'. I would call 'recent' less than 1 week.
A title that
is recent (November 6) is already listed (7.2)
Something similar occurs with Z Nation s04e06. Still shown at 0.0, while on IMDb it stands at 8.8, though this I could imagine being a caching 'thing'. It's only 3 days old and can be considered 'recent'.
Could perhaps the total amount of votes play a role in all this?
Anyway, it's not an enormous problem. It's just something I've noticed for a while now and (curious as I am) I'd like to know why this is happening.