.NET Core S2I docs says only version 1.0 is supported: https://docs.openshift.com/container-platform/3.4/using_images/s2i_images/dot_net_core.html While 1.1 is support is listed on the supported technologies page: https://www.openshift.com/features/containers.html
Already fixed in https://docs.openshift.com/container-platform/3.4/using_images/s2i_images/dot_net_core.html