It is possible to combine two signatures in a .sig file. But the representation of the results is not good if one or both signatures are invalid.
If the first signature in a file is invalid, only the result for that one is displayed:
If the first one is valid, both results are shown, but you have to look closely to see which signature was invalid:
Ideally, one would always be presented with both results and see at a glance which signature is valid and which not.
gpg's output indicates that gpg exits on the first invalid signature. This cannot be changed by Kleopatra. And I think it's irrelevant whether there are valid signatures if one signature is invalid. If you have a contract signed by multiple people then the contract won't be valid because two of three signatures are valid.
I checked who eats the second valid signature after the first invalid one. It's gpg in batch mode.
gpg (2.4.6-beta) with batch mode:
$ gpg --batch --status-fd 2 --exit-on-status-write-error --verify verify-me.txt.sig verify-me.txt [GNUPG:] NEWSIG gpg: Signature made Mo 17 Jun 2024 16:21:28 CEST gpg: using RSA key 5F4C389C9265ABDE08B21CEA41FAC215ADE1CB46 [GNUPG:] KEY_CONSIDERED 5F4C389C9265ABDE08B21CEA41FAC215ADE1CB46 0 [GNUPG:] KEY_CONSIDERED 5F4C389C9265ABDE08B21CEA41FAC215ADE1CB46 0 [GNUPG:] BADSIG 41FAC215ADE1CB46 Ted Tester <ted.tester@demo.gnupg.com> gpg: BAD signature from "Ted Tester <ted.tester@demo.gnupg.com>" [unknown] [GNUPG:] FAILURE gpg-exit 33554433
gpg without batch mode:
$ gpg --status-fd 2 --exit-on-status-write-error --verify verify-me.txt.sig verify-me.txt gpg: NOTE: THIS IS A DEVELOPMENT VERSION! gpg: It is only intended for test purposes and should NOT be gpg: used in a production environment or with production keys! [GNUPG:] NEWSIG gpg: Signature made Mo 17 Jun 2024 16:21:28 CEST gpg: using RSA key 5F4C389C9265ABDE08B21CEA41FAC215ADE1CB46 [GNUPG:] KEY_CONSIDERED 5F4C389C9265ABDE08B21CEA41FAC215ADE1CB46 0 [GNUPG:] KEY_CONSIDERED 5F4C389C9265ABDE08B21CEA41FAC215ADE1CB46 0 [GNUPG:] BADSIG 41FAC215ADE1CB46 Ted Tester <ted.tester@demo.gnupg.com> gpg: BAD signature from "Ted Tester <ted.tester@demo.gnupg.com>" [unknown] [GNUPG:] NEWSIG gpg: Signature made Mo 17 Jun 2024 15:52:13 CEST gpg: using RSA key 8EB9CBACA389D28CAA3CA15C1F5C8972CE8BFED7 [GNUPG:] KEY_CONSIDERED 8EB9CBACA389D28CAA3CA15C1F5C8972CE8BFED7 0 [GNUPG:] SIG_ID gsL8M7fTg6K9VLxI49P1Kir/qm8 2024-06-17 1718632333 [GNUPG:] KEY_CONSIDERED 8EB9CBACA389D28CAA3CA15C1F5C8972CE8BFED7 0 [GNUPG:] GOODSIG 1F5C8972CE8BFED7 edward.tester@demo.gnupg.com gpg: Good signature from "edward.tester@demo.gnupg.com" [ultimate] [GNUPG:] VALIDSIG 8EB9CBACA389D28CAA3CA15C1F5C8972CE8BFED7 2024-06-17 1718632333 0 4 0 1 8 00 8EB9CBACA389D28CAA3CA15C1F5C8972CE8BFED7 [GNUPG:] TRUST_ULTIMATE 0 pgp [GNUPG:] FAILURE gpg-exit 33554433