Explored Darkness feature with strange bug.

For some reason the explored areas wont always stay explored. I made a short video demonstrating the problem. Some times it works, other times it just bugs out. I have tried logging in as a player, as a gm, and with a players account.

Here is the video demonstrating the problem:

Roll20 explored darkness bug

And here is a link with a screenshot of the page settings:

Page settings

Anyone have any idea what is going on? All help would be greatly appreciated

UDL is like playing russian roulette with a fully loaded revolver.  Never run it in a live session unless you like wasting the players and yours time being QA for free.