In a folder, as standard user, when I try to add a global-scoped credential using the git implementation of the "modern SCM",  I cannot select any credentials while it is possible to select the credentails when selecting git the Legacy SCM.

As administrator, it is possible to select the global-scope credential in both (Modern and Legacy) implementation.

The issue seems liked to the fact that when using the modern scm In jenkins.plugins.git.GitSCMSource.DescriptorImpl.doFillCredentialsIdItems(SCMSourceOwner, String, String), the context parameter is null.

When the legacy SCM is selected, in the hudson.plugins.git.UserRemoteConfig.DescriptorImpl.doFillCredentialsIdItems(Item, String, String) method, the project is not null and the global-scoped credentials are listed.

When I try the same process at the level of a job, both the modern and legacy SCM are able to list the credentials.

The issue could be liked to JENKINS-38048.