Never had that myself. My family and i have been using it exclusively for years now.the only tine we fallback is when someone is in an area without data or wifi. Maybe once a year.

That's really weird. I use it for my out-of-band chat for work since we all mute our Teams after hours. It's been reliable the entire 3 years we've been using it. Maybe I'm just really lucky?

Do you have google play services installed? If not, your power optimisation settings might prevent signal from running in the background, which it needs to to receive messages

Weird I have never experienced this (or it was so long ago I don't remember). We've been using Signal absolutely reliably for our family Chat for many years now, and also with other friends.

I don't think Google Play Services are required, but

your power optimisation settings might prevent signal from running in the background

could have sth to do with it. And that's accessible through Settings, an App Permissions thing IIRC (although I never needed to do that manually either).

PS: I sent you a dm on a different matter.

Works on my machine. :P

Ive had this issue as well. I find it happens when i leave my wifi and go to cell signal. Not sure if its the same for you. I dont think ive had it be almost a week later but its been a few hours or maybe a day