When the yum client is configured to require GPG check and the contents of the repomd.xml have been rewritten the GPG check will fail with the following error:
http://localhost:8081/repository/newrelic/linux/yum/el/7/x86_64/repodata/repomd.xml: [Errno -1] repomd.xml signature could not be verified for newrelic-infra
This is reproducible using the remote:
The repomd.xml on the remote contains sqlite entries which are removed when the repomd.xml is written to the proxy repository. So the two files do not match.