Browser notifications very unreliable

Hello, I work with Windows 7 and the latest Firefox browser and keep myself very much on motor talk. I subscribed to a lot of posts to be pointed out to new answers. The so-called browser notifications in the corner, if the page doesn’t have the focus, are very unreliable with me. From other pages and forums I know it so that a notification occurs exactly when it occurs. I get notifications of posts, via replies v on people I’ve answered for a long time maybe 15 minutes before. Completely illusory is also the expectation that you will get a notification when an subscribed post has been commented on. Can I somehow influence that positively, or is that due to Firefox, or to the implementation on MT page? Thank you and many greetings, hadez16