Autominer not performing when at the side of the map and not in view

I have two auto-miners clearing Regolith, one two tiles from the side of the map, one at the side of the map. When they are not in view, they fail to perform. As soon as you look, they start clearing tons of Regolith they should have cleared before, like all the _other_ autominers.

The attached save shows this situation right when I looked. You will notice that the space-doors are open and all other Regolith has long since been cleared. This seems to happen consistently when I have not been looking at these two miners for a while. Note that for the attached save, I had to reload to get them to start mining effectively again. But on an earlier occurrence, just looking at the area of the miners started them doing their job again.

It should also be possible to get the issue again by letting the attached save run for, say, 30 cycles or so while having the view centered someplace else.

m064.sav