Details on CLBackgroundActivitySession and CLServiceSession Diagnostic enum

I am working with the CLBackgroundActivitySession and CLServiceSession to figure out why our app is sometimes terminated in the background.

I am unable to understand what "insufficientlyInUse" corresponds to, it could be understood as

1. The location data is not being used enough
2. the "While in use" permission is not enough

It will be very helpful if the entire enum can be explained, I am attaching the one for CLServiceSession since it is a superset of CLBackgroundActivitySession from CoreLocation

extension CLServiceSession {

    public struct Diagnostic {

        public var authorizationDenied: Bool { get }

        public var authorizationDeniedGlobally: Bool { get }

        public var authorizationRestricted: Bool { get }

        public var insufficientlyInUse: Bool { get }

        public var fullAccuracyDenied: Bool { get }

        public var alwaysAuthorizationDenied: Bool { get }

        public var serviceSessionRequired: Bool { get }

        public var authorizationRequestInProgress: Bool { get }
    }
      ...
}

Looking forward to hearing from you