Milk container (black) frothing issue

Greetings

I have a Delonghi eletta explore coffee maker with beans grinder. It’s about 3-4 months old. I’ve been using it mostly for cappuccino until the taste became bitter/watery and was unable to fix that. Then switched to flat white which has been fine until today. The black lid milk frothing container started acting up as at first for a second or two the milk pours from the spout as usual but then it becomes intense steam and no milk is coming out anymore. I tried cleaning all the attachments and the very inside of the black top of the container but nothing changed. Presumably I can replace the container itself but this is very odd and it shouldn’t be the case.

I have descaled very recently and I’ve been washing the container parts regularly when prompted by the coffee machine. Any advise of what the problem is, is there a fix for it with the current jug and how to avoid it in the future is very welcomed!