you may want to check the login of the Onesignal integration.
I tested it and what happens is than when a new comment is posted a push notification is sent to all push subscribers, not just to those who subscribed to an article comments.
This of course results in many users unsubscribing from the push notifications, as is very annoying.
I don't know if the Onesignal integration was supposed to work like this, but it think it should be aligned to Komento settings.
In my case a user receive a notification only if he has checked the "subscribe" checkbox before posting a comment.