This might be a little trick to describe but here goes...
It concerns MC's own file picker when pointing at a network storage device - for instance
Import / single folder / browse
In my case, this typically points fairly deeply down the tree of a NAS device. This picker (helpfully) remembers where it was last pointed. If you navigate up a couple of levels after pressing browse, the picker seems very reluctant to open other branches of the tree than the one originally open a moment ago. The native Windows equivalent file picker has no such difficulties. I think the problem is confined to network storage - AFAICT, local storage doesn't exhibit this problem.
This is hard to describe - easy to demonstrate. I hope there is enough information here to explain what's going on. It's possible that something isn't being refreshed as it ought.