Mux keeps re-notifying about past events (browser notifications, Safari)

I've noticed weird behavior for Mux notifications for a while. And today I realized I can easily reproduce this simply by changing between chats. When I select one Mux will re-notify the last message from that chat and constantly keep doing so if I jump back and forth between two chats.

Just reloading Mux will also re-notify for the active chat.