Hey @jason_engage,
Following up here, I can confirm that the reason this was removed was to clean up the duplicate headers. We are aware now that this has affected some partners that were relying on it so thank you so much for letting us know. I’m not sure if it will be re-instated, so going forward using the non-http version for checking rate limits is the recommended way to go.
Since you’ve already made the change you should be good to go from here on out.