We have SUMA 3.1.2 installed and are trying to sync a custom repo we created:
spacecmd {SSM:0}> repo_details "GitLab SLES 12-SP2"
Repository Label:                  GitLab SLES 12-SP2
Repository URL:                    https://packages.gitlab.com/gitlab/gitlab-ee/sles/12.2/x86_64
Repository Type:                   yum
Repository SSL Ca Certificate:     None
Repository SSL Client Certificate: None
Repository SSL Client Key:         None
spacecmd {SSM:0}> softwarechannel_details gitlab-12-sp2-pool-x86_64
Label:              gitlab-12-sp2-pool-x86_64
Name:               GitLab-12-SP2-Pool for x86_64
Architecture:       x86_64
Parent:             sles12-sp2-pool-x86_64
Systems Subscribed: 0
Number of Packages: 0

GitLab SLES12-SP2 x86_64

GPG Key:            E15E78F4
GPG Fingerprint:    1A4C 919D B987 D435 9396  38B9 1421 9A96 E15E 78F4
GPG URL:            https://packages.gitlab.com/gitlab/gitlab-ee/gpgkey

GitLab SLES 12-SP2
# spacewalk-repo-sync --channel gitlab-12-sp2-pool-x86_64
09:42:56 ======================================
09:42:56 | Channel: gitlab-12-sp2-pool-x86_64
09:42:56 ======================================
09:42:56 Sync of channel started.
09:42:58 ChannelException: GPG key retrieval failed: [Errno 14] HTTP Error 404 : https://packages-gitlab-com.s3-accelerate.amazonaws.com/7/11/sles/12.2/x86_64/repodata/repomd.xml.key?AWSAccessKeyId=AKIAJ74R7IHMTQVGFCEA&Signature=s9vWpuVMVOmjyn2vDhSl7jCZFSE%3D&Expires=1510674478
09:42:58 Total time: 0:00:01
Does SUMA not honour the "GPG URL" field when you create a channel? Why is it using the wrong URL for the GPG key?