Keychain Access for Pages Documents - Show Password Loop

I'm having the same issue as Keychain access - Password for Pages file… - Apple Community which I can see was left unanswered.

This is occurring for all .pages iWork Document Password keys in the Keychain Access application. Upon clicking 'Copy password to clipboard', nothing happens, the value in my clipboard remains whatever it was previously. Upon clicking 'Get Info' and then 'Show password', it asks for my login keychain password. Clicking 'Deny' and clicking 'Allow' have the same effect, the password stored does not show. Clicking 'Always Allow' stops the dialogue from coming up, and does not show the password. Other keychain items (eg Wi-Fi passwords) work completely fine, though I will note that the dialogue for them looks different.

Unlocking the keychain does not resolve the issue. Closing and reopening Keychain Access does not resolve the issue. Restarting my computer (hey, worth a shot) does not resolve the issue. The password is not present in the Passwords app. I'm on Sequoia 15.5.