How does the scrobbling really work?

Hi! I have a little problem with the episode scrobbling to trakt. It’s just not working reliably enough for me. I even had to turn it off and manually say with another app when I’ve watched an episode.

At what point does Infuse mark an episode as watched on trakt? It should be like a percentage of the episode but my impression is that it has to play until the end of the file, including credits for the episode.

Can you help me understand how this really works?

Thank you