The github and tekton endpoints were producing a content-type header of appplication/json when it was supposed to be application/json. After much debugging with rh-ee-jorringe and rhn-support-dehort we figured out this simple typo

Commit for IQE here: https://gitlab.cee.redhat.com/insights-qe/iqe-platform-changelog-plugin/-/commit/6ebbfb8920bc855323f84d4ee5fba34456d61316
Dev commit: https://github.com/RedHatInsights/platform-changelog-go/commit/78194db7cd9b29b06144845d43b8ac4dfe064de4