I had this problem several time in the past days with Version 7.0.4.
I watch a episode or movie on my iPad. The episode or the movie was completly watched until the end.
It was synced to trakt.tv as completely watched.
On my AppleTV with the same version of trakt, the episode and movie was not synced as watched, even if I trigger a manual sync.
On both devices i’m logged in with the same trakt account and icloud sync is active as well.