I am getting the same strange behavior.
When I search for "June" (in German "Juni"), there is list of for search result options:
- Items with the date "juni"
- Items with the text "Juni" embedded
- Items with Juni as part of the location name
- Items with Juni in the metadata

When I tap any of these results, the search will be repeated and the "date" result is lost.
To see all 3684 items with the date "June" I have to go straight for "All results" and refrain from tapping the date result with the calendar icon and just swipe up to reveal all results. But then the date results will be mixed with the other categories, like pictures of Juniper trees and documents showing the text "June".
You may want to report this bug using the feedback form, so it will be fixed sooner or later.