404 with forward package request .npmrc

I am currently getting the following error in ci and locally:

npm WARN deprecated @angular/flex-layout@7.0.0-beta.24: This package has been deprecated. Please see https://blog.angular.io/modern-css-in-angular-layouts-4a259dca9127
npm WARN deprecated core-js@2.6.12: core-js@<3.23.3 is no longer maintained and not recommended for usage due to the number of issues. Because of the V8 engine whims, feature detection in old core-js versions could cause a slowdown up to 100x even if nothing is polyfilled. Some versions have web compatibility issues. Please, upgrade your dependencies to the actual version of core-js.
npm ERR! code E404
npm ERR! 404 Not Found - GET https://.../api/v4/projects/140/packages/npm/sax/-/sax-1.3.0.tgz - Project not found
npm ERR! 404 
npm ERR! 404  'sax@https://.../api/v4/projects/140/packages/npm/sax/-/sax-1.3.0.tgz' is not in this registry.

I have “Forward package requests” enabled in Package Registry under: /admin/application_settings/ci_cd

my project .npmrc file



my user .npmrc file


I expected forwarding to work.
https://…/api/v4/projects/140/packages/npm/sax/-/sax-1.3.0.tgz to redirect to: https://registry.npmjs.org/sax/-/sax-1.3.0.tgz

I am on a self-hosted v16.4.0-ee instance.