If I create a filter like "Date updated is Last 2 weeks" there are many recently updated tasks that are missing from the view.
Strangely, if I change it to "Date updated is Last 2 days" (days instead of weeks) then some of those tasks (e.g., from yesterday) magically appear. Setting the filter back makes them disappear again.
Now, even stranger yet, if I change the filter to "Date updated is Next 2 weeks" (in the future) then some of the other missing tasks appear in this view, even though one would think that view should be empty.