XYplorer Beta Club

If I select "Show weekday" in the modification date tab, and the modified file is in the bottommost folder of, for example, four folders, only the bottommost folder shows as modified today. The folders above it show a different date. I remember that previously the topmost folder always showed today's date.
Did I accidentally change a setting?

If you mean when you modify a file that only it's direct parent folder mod date is changed, not the root folders as well, then that is how Windows works (at least NTFS), you're misremembering.

This is what my upper and lower folders look like. Both should display Wednesday in this case.

Show Weekday has AFAIK always only applied to the last 1 week period.

That's strange. I have a folder containing three files and a subfolder also containing three files.
The files in the first folder were edited yesterday. The files in the subfolder were edited today.
Why does the "Last Accessed" column for the top-level folder show "yesterday" and not today?
I accessed the top-level folder "today" to get to the subfolder, not "yesterday."

Accessed dates are unreliable, there are many factors that can delay/affect their updating.