Peculiar EXC_BAD_ACCESS, involving a Task

I had to update a simple piece of code, so it could be delayed by a few ms in some cases. This is how I tried to achieve that, by using a Task:

class SomeClass {
    private var availableStuff : Set<Stuff> = []

    func updateStuff(lookingFor prop: SomeProp,
                     updatedThing: String,
                     waiting: Duration = .zero)
    {
        Task {
            if waiting != .zero {
                try await Task.sleep(for: waiting)
            }
            
            if var stuff = availableStuff.first(where: { $0.prop == prop }) {
                stuff.thing = updatedThing
//                print(availableStuff)
                self.availableStuff.remove(stuff)
                self.availableStuff.insert(stuff) // BAD ACCESS here
            }
        }
    }
}

It did work before implementing the delay, but now it would crash at the insert statement (sometimes at remove). Naively, I put a print statement beforehand and to my surprise, this kept the crash from occurring at all!

I switched on Address Sanitizer, now it doesn't crash, even w/o the print statement.

• Am I using the Task wrong, somehow?
• How can I further diagnose this, so it doesn't happen later in production?
• Or should I just leave the print in and hope for the best?

Thanks!