The availability of HD may take a bit longer than other resolutions. We are working to improve this! If you prefer to wait for availability of HD, you can upload your video as unlisted and make it public once that resolution is available.
Appreciate the info. Please send a feedback report directly from YouTube with these steps: https://goo.gl/WdI0BK . While every individual report may not get a direct response back, we do review everything and use the details to investigate and fix issues. Thanks!