Property Filter on Documents not bringing up all docs

I was using my phone app to locate a document assigned to a specific property. Although I knew I had about a dozen documents for the property in question, only 4 showed up. Then I went to the online version on my computer. All the documents were there, as I had remembered, but when I tried to filter by property again, only 4 documents came up.
Is there a trick I don’t know about?