This relates to detached signature verification:

If the .asc file is empty, verification fails, and the status is set to 'error - verify 4294967295'

That is OK, although the status is not very helpful.
However, if the asc file contains some text (but is not a valid sig), then verification fails and status is not set.
This does not seem right.
If debug is enabled, the following messages are shown:

[GNUPG:] NODATA 3
message ignored: NODATA, 3
[GNUPG:] NODATA 4
message ignored: NODATA, 4
gpg: no signature found
gpg: the signature could not be verified.
Please remember that the signature file (.sig or .asc)
should be the first file given on the command line.
gpg returned a non-zero error code: 2

I think it would be useful to process the NODATA messages.
The value 3 means 'Invalid packet found'; 4 means 'Signature expected but not found'
Either of those would be better as a status than None.