This is the validation result if you sign a file and after that change its content:
{F5387673}
I think the wording could be improved. We should at least add some more information, as IMHO for a user the combination of "The signature is VS-NfD compliant" and "The signature is invalid: Invalid Signature" is contradictory. As well as linguistically ugly with the doubling of "invalid".
Edit (2024-06-18):
We decided to overhaul the message completely, not only for invalid signatures, but for the valid ones, too and combined decrypt/verify.
The details have still to be decided.