Broken VSYNC with Metal driver

[caco-underscore]

On M1 running macOS and ProMotion enabled (120hz), if I switch between fullscreen Xcode and a SDL2 window, SDL_RenderPresent() changes from waiting for vblank (expected behaviour) to not wait and use 100% cpu if not more (Xcode shows 150% usage for the example bellow). This only happens with the Metal driver; OpenGL driver behaves like it should. This is the test code in c++:

#include <iostream>
#include <chrono>
#include <SDL2/SDL.h>

int main() {
    SDL_Init(SDL_INIT_VIDEO);
    SDL_Window* window = SDL_CreateWindow("V-Sync Example", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, 0);
    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);

    SDL_Event event;
    bool running = true;

    // render loop
    while (running) {
        
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_QUIT) {
                running = false;
            }
        }

        // Clear the screen
        SDL_RenderClear(renderer);

        // Measure V-Sync wait time
        auto start = std::chrono::high_resolution_clock::now();

        SDL_RenderPresent(renderer);

        auto end = std::chrono::high_resolution_clock::now();
        auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
        std::cout << "Time spent waiting for V-Sync: " << duration.count() << " milliseconds" << std::endl;
    }

    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 0;
}

The lib version I'm using is 'stable 2.30.8' from Homebrew.