memory race on deep looper

Below is some simple code that does nothing, saves nothing. Yet the memory usage keeps rising. Am I missing something or is this a bug? The code requires 6 core CPU minimum. ContentView.swift

import SwiftUI
import Combine

struct ContentView: View {
    
    @EnvironmentObject var loopClass:LoopClass
    
    var body: some View {
        
        ProgressView(value: Float(loopClass.loop_count), total: Float(loopClass.max_loops) ).progressViewStyle(.circular).padding()
        
        Button("Run looper", action: {
            loopClass.loopFunc()
        }
        )
    }
}

LoopClass.swift

import Combine

class LoopClass: ObservableObject {
    @Published var loop_count = 0
    @Published var max_loops  = 0
    
    func loopFunc () {
        let loopSet = [ 1, 3, 5, 7, 11, 13 ]
        
        max_loops = Int(pow(Double(loopSet.count), 13.0))
        print("max_loops = \(max_loops)")
        
        for loop13 in loopSet {
            
            DispatchQueue.global().async {
                
                for loop12 in loopSet {
                    for loop11 in loopSet {
                        for loop10 in loopSet {
                            for loop9 in loopSet {
                                for loop8 in loopSet {
                                    for loop17 in loopSet {
                                        for loop16 in loopSet {
                                            for loop5 in loopSet {
                                                for loop4 in loopSet {
                                                    for loop3 in loopSet {
                                                        for loop2 in loopSet {
                                                            for loop1 in loopSet {
                                                                DispatchQueue.main.async{ self.loop_count += 1 }
                                                            }
                                                        }}}}}}}}}}}
            }   //  DQ
        }       //  for loop13
    }
}