In the case of arming multiple keys when running keyholder arm, if for one of those keys the password is not known, there is no way to proceed with the others skipping that one so to have keyholder arming all keys but the one without password.
Keyholder keeps asking for Bad passphrase, try again... and it doesn't give up after a reasonable number of failed attempts. Hitting ctrl+c exists leaving only the previous keys armed.
The workaround used to go past this have been to temporarily rename the offending key so that it will come last in the alphabetical order of the keys listed in /etc/keyholder.d/.
See also T224887#5232493