LM 22.2 Cinnamon ISO failed Verification with misleading errror message

The tool shows an error message which might be misleading for unexperienced users:

mint-iso-verify linuxmint-22.2-cinnamon-64bit.iso
Checking /home/[user]/Downloads/linuxmint-22.2-cinnamon-64bit.iso
Importing 27DEB15644C6B3CF3BD7D291300F846BA25BAE09 from hkp://keyserver.ubuntu.com
Deleting 27DEB15644C6B3CF3BD7D291300F846BA25BAE09
Importing 27DEB15644C6B3CF3BD7D291300F846BA25BAE09 from hkp://keys.openpgp.org
Deleting 27DEB15644C6B3CF3BD7D291300F846BA25BAE09

(GUI:)
unknown signature
key not found on key server
signed by: 27DEB15644C6B3CF3BD7D291300F846BA25BAE09

Reason is ONLY the missing Linux Mint signing key which must be re-imported
gpg --keyserver hkp://keys.openpgp.org:80 --recv-key 27DEB15644C6B3CF3BD7D291300F846BA25BAE09

For the default mint-iso-verify tool it seems a little strange that just its very own signing key is marked only as "unknown signature" and "key not found on key server" without any further explaination.

This type of error message didn't pop up in previous releases (?)

Start with the mint-iso-verify command and trace the handling of the unknown-signature and key-not-found results shown in the report. Confirm how the GUI and command-line messages are produced; done means a missing Linux Mint signing key is explained clearly instead of only reporting an unknown signature.