Incorrect Data When Logging In

When I first fire up Trakt on my PC why do I not get correct data?

As can be seen below on the left is my History clearly showing the TV Show House of David Season 2 Episode 3 as being watched, but on the right, when I go into the Show itself, S2E3 does not show as watched.

Why does this happen? Unless I go and Reset Browser Data and then refresh my show page.

Why do I need to do this after just logging on?