I have a PWA that also relies on mobile push notifications. The notification code is here. Without them there is no point in the app existing. I've tested desktop Firefox and Chrome, both work fine, and iOS mobile safari saved to Home Screen (PWA) has issues. I see in consistent responses from pushManager.getSubscription(). the user excepts notification permission, then I create a subscription and save it to my server. at this stage everything works fine. if I close the app (swipe it up and away) then reopen the app pushManager.getSubscription() return null but notifications still come through. Since the response is null the UI shows a "subscribe" button. If you click it, another subscription is created. Now every notification get delivered twice because the initial subscription, while null on the device still exists in my server.