I confirm there is a bug. In the list of the show, the episode is listed as “not watched”, but if you open the episode or series, the episode is listed as “viewed” .
Thanks for reporting. What version of SeriesGuide are you using? The latest beta calculates the next episode differently, e.g. if an episode is watched multiple times it shows the next one with less times watched. So: is the episode right before watched more than once?
Erm not sure of your question but I marked them as watched on trakt TV web interface once for episode until 8 for B99 latest season, however in series guide, as in screenshot its still not marked as read. Although if I manually click the show and check, it correctly shows ep 8 as already watched
This is also the case for ep7 too but for that I manually check the watch tick mark in the main series guide shows list. (ep1 to 6 I manually mark as watched inside series guide so didn’t realise the issue earlier)