fakeClient.Delete(obj) doesn't update deletionTimestamp of the obj passed to the function. The bug is in fakeClient.deleteObject, since it gets a new object and updates the new object without rewriting the original object.

Reference: https://github.com/kubernetes-sigs/controller-runtime/blob/v0.19.0/pkg/client/fake/client.go#L1085-L1095