unusual issue with the map

[:1]Hi, I hope someone can help me here.

I began having an issue in the sewers part of Act 3 on hell mode, where the area of the map I've explored, goes back to being unexplored whenever I go through a portal, a way point, or save/exit the game. Now this issue has occurred in every map following.

I am playing the game on single player on OSX platform. I have version 1.13. I've tried searching for similar issues on this site and blizzard but I've not found a similar issue as of yet.