Hi,
Sorry if this was already posted before but I did a quick search and did not find anyone describing this bug.
I've just watched two episodes and it seems that the player the time bar does not know well if the video was paused or not. Indeed, for these two episodes I paused the video for maybe 10-15 minutes and twice it ended the video 10-15 minutes before the end with a popup to launch next episode.
I am currently running the store version of MOL2 but did not see anything in the betas changelogs that would fix that bug.