quest leading to cruel act 1 problem

At the end of act 3, we entered cruel act 1 after using the time portal. However, it was in the town at "old time." The quest leading to cruel act 1 did not mark as complete this way. We have to use the time portal at "current time."
This incomplete quest will block players "mapping" the end game.

No, open non-main quests don't block a player from playing endgame.

If you mean the message "you have to finish the campaign first", look at my answer in I FINISH CAMPAIGN but I CANT DO MAPS.