Telltale is saying there is going to be a delay while they work on performance issues.

"The team is working on episode 4 on Steam to release in conjunction with a performance patch, and it should be available later today (PST)."

Source: https://telltale.com/community/discussion/comment/2631190/#Comment_2631190

AGAIN?

Also what preformance issues? Every episode laggs at some point.

Dahaka on Steam is out. Only GOG and mobile is screwed.

Apparently it was particularly bad in Episode 4, so they had to delay it. But now that's it's released on Steam I am not sure what the hold up is