oc exec is ignoring HTTP proxy settings

Issue

When executing oc exec the proxy configured with HTTP_PROXY is ignored.

Other commands such as oc logs -f are respecting HTTP_PROXY and are working fine.

A command like oc exec -p xyz-6-aabv1 -- id fails with:

error: Error sending request: Get https://master.example.com:8443/api/v1/namespaces/test/pods/xyz-6-aabv1/exec?command=ls&container=xyz&stderr=true&stdout=true: dial tcp X.X.X.X:8443: connection refused