Request headers set by user are used only in the initial request, and not in subsequent requests

Bug report

Describe the bug

My streaming service does not have a Kodi client, so I maintain my own. For authentication, certain HTTP request headers are required to be set. I am setting those via this line in my add-on:

"inputstream.adaptive.manifest_headers": urlencode(ISHeaders)

ISA is using the headers correctly in the initial request for manifest. Using Fiddler, I intercepted HTTP(S) traffic. See highlighted in red rectangle in screenshot:

mpd-req

But in the subsequent request to actually get the individual video segment files mentioned in the mpd manifest, these headers are not used. See "User-Agent" in screenshot:

dash-req

Expected Behavior

Headers (those that are relevant) set by user should be used in all subsequent requests.

Your Environment

Used Operating system:

[ ] Android
[ ] iOS
[ ] tvOS
[ ] Linux
[ ] OSX
[x] Windows
[ ] Windows UWP
Operating system version/name:
Kodi version:Nightly build KodiSetup-20240429-625be876-Omega-x64
inputstream.adaptive version:

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xbmc / inputstream.adaptive