Quay operator project remains in Terminating

Hi,

 My customer is having the following issue in Quay 3.5.1:

The project where the Quay operator is installed remains in a Terminating when deleting the project. We have to remove the project manually by removing the finalizers.

The message that is shown:

• lastTransitionTime: "2021-05-20T13:28:02Z"
  message: 'Some content in the namespace has finalizers remaining: quay-operator/finalizer in 1 resource instances'
  reason: SomeFinalizersRemain
  status: "True"

I have tested this with 3 projects. All projects had the same issue. When i execute a oc get all -n <project> i receive a message that there are no resources in the project.

$ oc get all -n quayinstance
No resources found in quayinstance namespace.