You are using the pesign-obs-integration binary package from SLE12, with the canned SLE12 certificate. What I mean is to linkpac/copypac openSUSE.org:SUSE:SLE-12-SP2:GA/pesign-obs-integration into OpenHPC:1.3, that way it will get rebuilt and store the OpenHPC certificate. The second option is of course to patch the KMPs to have # needssslcertforbuild.