Please add to the comments if you are experiencing this. I would like to know the OS and device you are using as well.
I’ll bring this feedback to the feature team and help get this investigated.
I'm also on a Mac - I don't receive any notifications and need to check manually. I rely on notifications that are consistent with Slack, What'sApp and Skype but not for Teams. I have the same problem on my iPhone. I have the latest operating systems and constantly do updates. I'm considering changing our group to another option.