Map chests seem to be broken/not working

In delve city rooms with map chests, AND temple rooms with the "dusty charts" chests (i.e., i the cartography or storage rooms), I am consistently getting zero map drops. This is not a filter issue, as I've turned the filter off to check. Occasionally sextants will drop, and that shows up fine, but the chests are otherwise entirely empty.

Is anyone else having this issue/is it a known bug?