Push notifications sometimes disappear immediately

In a 1:1 encrypted chat, I've noticed that often (but not always, maybe 2/3 of the time), notifications disappear shortly after they appear and my phone vibrates. When this happens, the dot signifying new notifications on the element app icon also disappears.

I'm currently using version 1.2.1 on a Pixel 5 running Android 11, but I've noticed this issue for a few months on both this device and a Pixel 3, also running Android 11.

[Here's a video](https://streamable.com/focnm4)