Using "Date Modified" field in Keychain Access utility app

Hello,

While browsing through the hundreds of entries in my iCloud Keychain, I noticed that many of them show the same date and time in the Date Modified field, to within a couple of seconds. Seems a bit suspicious to me! So I did a few experiments with inconsequential website logins to try to figure out what actions will change the Date Modified value. It seems that just using Keychain to enter a password will update this field to the date and time of the request, even when no password change is made. Does anyone have any insight on how this works, or what sort of events (benign or otherwise) would set Date Modified on huge numbers of records almost at once?

Thanks in advance for the help!