Call actor-isolated function backed by a DispatchSerialQueue using DispatchSerialQueue.async

In What's New In Swift, a new DispatchSerialQueue-backed actor was introduced. We're able to call MainActor-annotated functions using DispatchQueue.main.async without errors or warnings. For example:

@MainActor
func randomFunc() {
 print("Hello World")
}

DispatchQueue.main.async {
    randomFunc()
}

However calling a globalActor-annotated function or a regular actor-isolated function backed by a DispatchSerialQueue, we get the warning Actor-isolated instance method 'randomFunc()' can not be referenced from a non-isolated context; this is an error in Swift 6. Code here:

actor MyActor {
    private let queue: DispatchSerialQueue

    nonisolated var unownedExecutor: UnownedSerialExecutor { queue.asUnownedSerialExecutor() }

    init(queue: DispatchSerialQueue) {
        self.queue = queue
    }

    func randomFunc() {
        print("Hello World!")
    }
}

let queue = DispatchSerialQueue(label: "actorQueue")
let actor = MyActor(queue: queue)
queue.async {
    actor.randomFunc() // Warning here
}

Although it has a warning, the code still runs successfully and prints Hello World, but it would also do so from another DispatchQueue not used by the actor (this was tested in Version 15.0 beta (15A5160n) Playground).

My question: Can we remove the warning resulting from calling an actor isolated function backed by DispatchSerialQueue A using A.async { }, if that's safe behavior? If it's not safe, why not?