Multiple headers not being added

I am using a script that adds multiple headers but only the last one is added. I tried moving headers around and changing format (space rather than tab for example) but the behavior is consistent: only the last addHeader is added. Is this an issue with H2?

To make sure it was not a script error, I used the example on the thread https://www.webpagetest.org/forums/showthread.php?tid=630

The result is that only the last addHeader is added (and the UA is not changed) http://buff.ly/2mETSQC

Is there something wrong with my script?

setHeader UA-CPU: none-ya
addHeader xPat: My-Header
addHeader Pragma: akamai-x-cache-on
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