Apt proxy is not signed

I’ve configured a few apt proxies (NXRM v3.29.2) and they appear to be populating correctly, however after configuring my apt client to use these proxies (just using /etc/apt/sources.list, no auth), I get this when trying to use it:

W: GPG error: https://nexus.company.io/repository/Ansible-Bionic bionic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 93C4A3FD7BB9C367
W: The repository 'https://nexus.company.io/repository/Ansible-Bionic bionic InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.

I can use the --allow-insecure-repositories flag to apt-get update and --allow-unauthenticated with apt-get install but is there a better way?

Did I miss something?

Same here. OSS 3.28.1-01 with proxy apt repos for security.debian.org and deb.debian.org.