Some known items in collection do not show up in Browse By Issue Date and do not filter by date

[caflynn]

Describe the bug
I searched for a particular known item in the Undergraduate Research Collection on the collection homepage using the Browse function. If I filter by year, in this case "2019", no items show up as seen in this screenshot: https://uoregon-my.sharepoint.com/:i:/r/personal/cflynn_uoregon_edu/Documents/ScholarsBank/Undergrad_Research_Symposium/Scholars-Bank-Browsing-Undergraduate-Research-Symposium-by-Issue-Date.png?csf=1&web=1&e=EE3T0H

There is at least one more known item from 2019, and the results in a search are as above.

Similarly, if I Browse by year, filtering for 2016 and look for a known item for that year, I am not able to locate it in the list that results. In this case, the know item is this paper by Samantha Lowery. Here is a screenshot of the search filtered by year.

As a result, the number shown ("Now showing 1-5 of 5) is also incorrect.

To Reproduce
Steps to reproduce the behavior:
The behavior can only be reproduced by searching known items that "happen" to not show up? I discovered this incidentally because I knew there were at least a couple of entries for 2019 in this collection. I was able to find them by searching the full db on the title page by author. Likewise, I also realized there was at least one item missing when I looked at the list of items for 2016 elicited by Browse search of that year in the same collection.

Expected behavior
A clear and concise description of what you expected to happen.

Related work
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