I too had this issue. I appears that notifications don't show in full screen mode. When I returned Chrome to a windowed app on my Mac the notifications appeared.
I think I ran into the issue before as well.. however, I think that's an issue with how Chrome handles its notifications. I don't think there's anything in the library that could cause this behavior. A known issue is that the library is currently broken in Safari. I will investigate why when I have some free time.