Building APK packages for Alpine Linux (abuild)

Hello all, Alpine is awesome.
Alpine is an amazing project, and super important for Docker and micro-services.

We are working on a tool-set to build Alpine APK packages, so one could host any odd packages that anyone might need.

So far we had success building individual packages, signing the indexes, pushing the packages to our Amazon AWS s3 repo, baking-in the public keys for the repo in to alpine, and installing the packages without any issues.

Since then, we created a more automated way of building packages with jenkins + docker.
Now, we are having some unexpected signature/key verification issues when trying to install a package that was built with these tools, and I hope some one here can help me.

The output from abuild suggests that the packages are correctly signed.
There are no conflicts from  apk update about invalid keys.
But when I attempt to install the package from our repo  apk add nginx@ourrepo  , apk complains that we have have a bad signature:

/ # apk add nginx@ourrepo
(1/2) Installing pcre (8.37-r1)
(2/2) Installing nginx@ourrepo (1.9.7-r0)
ERROR: nginx-1.9.7-r0: BAD signature
1 errors; 30 MiB in 20 packages

I have some questions about the signing and how ABUILD works in general:

1) Does the filename of the public key in  /etc/apk/keys   matter? Is the filename parse in any way?
2) Does the  PACKAGER="yourname@aol.com" in  /etc/abuild.conf matter (at time of signing)? Is there a comparison/check of the PACKAGER value in abuild.conf with the name you enter when generating the key pair?  docker run --name keys --entrypoint abuild-keygen -e PACKAGER="Your Name <yourname@aol.com>" andyshinn/alpine-abuild -n
3) Is there a way to check, verify what apk expects to be the correct signer for the public key?

Any help is much appreciated!!

Project that does the APK building:
https://github.com/madedotcom/alpine-jazz-hands