Photos not finding referenced files

• Thanks for the replies
• First some data points -- All 38,000+ photos and 450+ videos being accessed by the Photos app are referenced. They are on the internal 2TB Flash Storage taking up 283GB. There is 1.28TB still available.
• I have only one Library, it is located in Pictures, it is designated as the "System Photo Library"
• I am not using iCloud Photos, My Photo Stream or Shared Albums
• These same items were referenced under Mojave and earlier OS using both Photos and Aperture on this iMac Pro
• The files missing references are a very small portion of the library.
• When one clicks on the "white icon w/red line" it says "locate referenced file", clicking on this sometimes brings up Finder sometimes not, when it does bring up Finder and you select the folder where the file is present, sometimes it repairs the link sometimes not.
• My work around is to delete the file missing the reference and the reimport it.
• Some of the "repaired" files have stayed repaired, some have missing references that show up days later.
• Since the reference process seemed to be working prior to Catalina, my first inclination is to believe the changes made as part of Catalina play a role
• Many thanks for your help

• All of the referenced files are within folders within the "Documents" folder of the only "User"
• The missing reference can apply to .jpg, .jpeg, .tiff and various video formats
• The file can sometimes be opened with "Open Viewer" from the Image pull down menu
• The file can sometimes be edited
• While clicking on the reference icon in upper right corner of photo usually produces no result, sometimes the Finder will open if "Show Referenced File in Finder" is selected in the File pull down menu
• The Color Profile on the ones I checked appears to be the same for both linked and unlinked
• As admin I have read/write permissions for all

I should have added that I ran "First Aid" it came back clean for both volumes of the internal Macintosh HD