content-type in csp report on fetch is missed

[maxkuzmin]

When csp report is initiated by browser and fetched by service worker, content-type header of request is missing for some reason. I created a demo page.
Being on loaded page, please open network, filter request by "report" substring and reload the page. You will see 4 requests:

• report1 xhr
• report csp
• report1 fetch
• report fetch

report1 is called manually from javascript (new XMLHttpRequest()...), report - by browser because of csp rule violation.
Both report1 xhr and report csp calls have "Content-Type: application/csp-report" provisional request header. However, only report1 fetch has such header, report1 fetch lacks the Content-Type header.

Tested in latest Chrome and Firefox.

[jakearchibald]

This sounds like a browser bug. Can you file it in the browser trackers?

[bathos]

Although this is not a SW-spec issue, very grateful that Google turned up this confirmation that I’m not just losing my mind.