I did a migration of Keychain items between Macs and MacOS was prompting me to type the password twice to authorise access.
To avoid this Apple suggest changing the password of the Keychain “login” (the problematic) and setting it back to the same password. This did fix it for me but the option to change password was greyed out on Keychain Access.
So, I had to create a new Keychain (no matter the name this will be temporary), then setting this new keychain as the default and now I was able to change the password on the “login” keychain.
Then, I just set the “login” keychain back as the default and deleted the temporary one (references+files option on delete).