Hi,
I think I may have a solution for you. I was struggling with this for last several months (btw also using SecCodeCopySigningInformation), always getting back to investigate and never found a solution until now. It definitely isn't just a log noise, but a real signing problem, which could potentially block release though app store.
First, some advice, which will save your time:
You might find suggestions like using com.apple.developer.networking.multicast entitlement - doesn't work, you are able to build and sign system extension, but it crashes with signature error when OS tries to load it.
Enabling Sandbox doesn't help either- but I definitely recommend enabling Sandbox for system extensions, you will need it for future release on App Store, if you plan it, and if you need to store/cache data, you can do it in protected group container with Sandbox on. It's worth the effort to Sandbox system extensions, although when pulishing notarized apps outside of App Store, it works without Sandbox.
One of the 2 messages generated complains about applicaiton.group. Ignore that. If you need to communicate through XPC, you need app group anyway.
You might find a suggestion to add keychain.access.group entitlement com.apple.token - forget it, it doesn't work with system extensions, you get a signing error when building. Although Apple's doc says com.apple.token is allowed by default, it is very likely tied to another entitlement, perhaps related to biometric reading. But keychain access group is actualy the culprit.
SOLUTION:
Define at least one keychain.access.group entitlement with your group ID in it, example: ABCDEFG.com.company.firewall
<key>keychain-access-groups</key>
<array>
<string>$(TeamIdentifierPrefix)com.company.firewall</string>
</array>
If you do that, "invalid application signature or incorrect provisioning profile" log message will go away.
Explanation:
When creating bundle id, you cannot select/deselect keychain access group (there used to be a checkbox for this couple of years ago, if I remember). Provisioning profiles are now automaticlaly generated with keychain.access.group added, so you have to define it even though you don't need it.
Regards,
Robert