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 am not receiving any notifications by email, only on the app. I am using Macbook Pro with Touch Bar, Mojave 10.14. I selected "General ->Follow this channel" and under Settings ->Notifications, I selected "Banner and email". I have no way of know if my team has added ro changed anything in other tabs, such as Excel, PowerPoint, and MindMeister, etc. This is vitally important for what is supposed to be a collaborative tool.