Almost every app that I allow notifications on (I turn notifications off for a lot of apps). Facebook and Facebook Messenger are the consistent ones. Also my Ring and the MyQ app for our home alarm and garage door. Messages does, Instagram does. Gmail usually does NOT have this problem though. I just Force Stopped Facebook, Messenger, and the My Q all because they're currently the ones repeating notifications from 2 hours ago...also cleared cache. Will let you know if that DOES work...not expecting that it will be a solution, though, as it affects many apps and not just one or two.
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