Persistent notification sounds while wireless charging?

Just started happening within the last couple of weeks, but everytime I put the phone on its charging stand, something seems to trigger a notification announcement when there's no reason to notify. And the closer the phone gets to 100%, the more frequent the notification chimes get.

It's kind of like the alarm sound Accubattery makes when the battery reaches your pre-set charging limit only more insistent and persistent. But I uninstalled Accubattery some time ago, and I don't use any battery saver or cleaner apps.