Map unexplores itself

The past few weeks I have had this problem with every clean build. Large portions of the map revert to unexplored status, but it happens seemingly randomly. It may have something to do with moving far enough away from my starting location. In this instance when the revert occurred I was actually within the Unexplored area and the game would not reveal the map south of a certain line. (The provided picture fails to show my character within the unexplored region, but it does show the unexplorable line.)

Is there something wrong with my setup or is this a bug?

These symptoms could be explained by unexpected program exits, when you close the program you need to quit from the main menu, not close the terminal window. (Don’t know if you’re doing that, but it has caused these symptoms in the past)
If that’s not it, it might be continuing issues with autosave.

Yeah this was from one continuous play. It didn’t take all that long actually.

I thought it was some temporary bug that would get fixed, but alas it has persisted between builds.

Would it still be a problem with autosave if I haven’t saved and reloaded? Is there any way to turn off autosave to check for that?

If you never exited the game it’s definitely a bug, but I’m really surprised you’re the only one reporting it if it’s that easy to trigger. No idea what the problem is offhand, I’ll have to look into it.

I am surprised as well. I am at a loss as to how to reproduce the bug, however. It has occurred after (but not only after) using the “Reveal Map” debug option. It sometimes occurs when switching z-levels. So far, it has only occurred outside of cities. It has occurred several times in one continuous play session.

Hope some of this helps. Is there any other information that would help with debug?