AI Pathfinding issue

[Beoric]

I am getting some irregular behaviour from the AI pathfinding on one of my maps. There are two sections of the map, North and South, which are separated by a secret door, signified by a VBL and MBL line separating the North from the South.

In the North portion of the map, with AI pathfinding turned on, the pathfinding operates normally; that is, squares are counted and obstacles are avoided.

On the South portion of the map, AI pathfinding does not operate at all. No paths are traced, and the movement counter is always at zero. Basically, it behaves as though the entire area was covered in a MBL/VBL, which it is not. If I turn off pathfinding, it does count squares, but does not navigate.

When AI pathfinding is on, if I erase the MBL separating North and South, the North takes on the properties of the South. That is, no square are counted and there is no navigation in either section. It is as if the South contaminates the North with whatever the problem is once there is no MBL separating them. If I draw a MBL or VBL line (it works the same eith either, or both) dividing North from South again, the North again counts squares and had navigation, but the South does not.

Moreover, if I draw an MBL further south along the corridor, the area where pathfinding works increases. If I move into the nearest intersection, I can get pathfinding to work if I use MBL to block off some branches of the dungeon, but not others. I'm currently moving MBL barriers around to see how big an area I can open up to functional pathfinding, but as you can imagine it is a laborious process, and I am no closer to figuring out why it works this way.

To be clear, there is sufficient light, the areas in question are clear of any blocking. Does anyone know what is happening here?

[aliasmask]

We would need a copy of the map to reallly investigate. But AI pathing is good for regular vbl/mbl but when using the other types it doesn't track very well. Pit, Hill and new one need solid areas and when in those areas the movement remains at 0 with AI on, but acts normal with it off.

[Beoric]

There are no pit or hill layers on the map, and just about everything else is rectangles.

In any event, I fixed the problem without solving it. I made some long, narrow tokens with MBL which I moved around to gradually narrow down where the problem was. At one point there was a dead end, and I kept pushing toward it, and the area that was working got larger, and the area that wasn't got smaller, and eventually I pushed the MBL token past the dead end, and the problem just disappeared in that area. And so I tried it in a different area, and the same thing happened. And now the whole map works perfectly. Whereas trying things like restarting the application did nothing. It's the weirdest thing.