Hi,
I’m the maintainer of What’s up Docker?; a tool tracking container updates using the Docker Registry API V2.
Until a few weeks ago, it was perfectly working with the lscr registry.
But now, the lscr API is responding with 401 errors (authentication required).
The issue is easy to reproduce
$ curl -i https://lscr.io/v2/linuxserver/radarr/tags/list
HTTP/2 401
date: Sat, 23 Jul 2022 09:30:00 GMT
content-type: application/json
content-length: 73
www-authenticate: Bearer realm="https://ghcr.io/token",service="ghcr.io",scope="repository:linuxserver/radarr:pull"
x-github-request-id: D1A2:B748:A8236E:B4E296:62DBBF98
strict-transport-security: max-age=15724800; includeSubDomains
{"errors":[{"code":"UNAUTHORIZED","message":"authentication required"}]}
Based on the headers above, I guess that I need to authenticate to the Github registry with the repository:linuxserver/radarr:pull scope but I don’t understand neither HOW nor WHY?? 
lscr.io was supposed to be a simple proxy in front of the real backend (ghcr or any other one) but apparently it’s not.
For the record, if I replace the registry name lscr.io/linuxserver/radarr:4.2.0-nightly by the real registry backend ghcr.io/linuxserver/radarr:4.2.0-nightly, all is working as expected.
Does someone have any clue regarding what’s changed over the last few weeks?