Drilllthough sometimes does not pass filter

No, it is is a single drill through filter.   In your example of country, I might drill through to England, France and Germany one at a time, but when I click on Spain up comes Italy.    I go to desktop and discover that at the last publish Italy was in the drillthrough filter,  So something is making occasional rows not pass the right data.   I have double checked that the field on the rows is the exact field in the drillthough filter on the target page.   It is very inconsistent and hard to reproduce, but I have seen it enough to know it is not my imagination.

I have been using bookmarks a lot, that's different, I am not confused.