I wrote a post that explains the issue fairly thoroughly: https://zwiftinsider.com/companion-app-favorite-notifications/
I’ve been pondering this a bit, and I think this is actually a very important bug to address… because these notifications are an important part of keeping Zwifters engaged, and building the community! Even if the weather is nice and you’re not Zwifting a lot, seeing that others are doing it keeps Zwift “on the mind.” That’s important. And giving more Ride Ons… that’s always a good thing.
Anyway, I wanted to post this as a bug report because it appears to be an issue for a LOT of people.