Neal Kindschi: Scott Clark Then I am mistaken. Carry on
Micah Fisher-Kirshner: No, been on the other end where the x robots noindex tag takes predominance over the page html index tag
Jesse McDonald: I`ve had them ignore a page set to noindex/no follow from the second it was published. I had to set the page to noindex/follow and submit it to index which then took it out.
Richard Hearne: The biggest problem I`ve seen with using directives via headers - and this applies more to larger websites that use third party CDNs, caching services and the like - is that you might not be serving the same headers to Googlebot that you expect.
Have you tested the page in question via Search Console and looked at what Google is getting?
Second theory - are you sending conflicting directives with the same page?
Third theory - have you carefully checked to ensure that what you`re sending in the header is correct?
Have any of you had cases where Google seems to completely ignore x-robots-tag: noindex? 
