It seems that Repman is requesting the wrong metadata endpoint from Packagist.
Currently it tries to fetch:
https://packagist.org/p2/psr/http-client-implementation.json
However, this package should be resolved via the providers endpoint:
https://packagist.org/providers/psr/http-client-implementation.json
Because of this, dependency resolution fails or returns incorrect responses in some cases.
Please verify the metadata URL generation logic for virtual packages and provider listings.
Let me know if you need logs or additional debugging information.