Gmail notifications not appearing on both devices

I just got an iPad and I’ve noticed that between my phone and my tablet, only one gets Gmail notifications at a time. Sometimes it’s the tablet, sometimes it’s the phone. I would expect both get the notification and dismiss when it’s been viewed on a device (laptop, phone, or tablet). To be clear, I’m using the Gmail app.

I’ve already tried to uninstall and reinstall on both devices to no avail.

Any idea what’s going on?