Downstreamed bug fix from @embroider/addon-blueprint#155
See embroider-build/addon-blueprint#155 for more information.
Migration guide
My attempts to migrate ember-container-query and embroider-css-modules suggested that, if the addon has relative paths, we now need to explicitly add the extension .ts.
This, in return, may require updating tsconfig.json to include the compiler option "allowImportingTsExtensions": true.