Forking Repo with "Inherit permissions" checked doesn't inherit groups permission properly (BB-5023)

If I check the "//Inherit repository user/group permissions//" checkbox and fork a repository that has only the "//Administrator//" group with write access, the expected result is having the new repository also with only the "//Administrator//" group with access to it.

And what is happening today isn't that, as illustrated on the attached prints (order: bb1.png > bb2.png > bb3.png).