Ok, first I really want to Thank the original poster and other members of this thread who just saved me from insanity. An UI I'm developing makes heavy use of both the Tradingview chart embedded module and the websockets, which were mentioned above as the "cashback monitor" triggers. I noticed that the UI started to freeze often lately and spent a couple of days profiling memory usage left and right until I spotted that satanic beast in the Task Manager (apparently, the only place in the browser where technically inclined users may accidentally notice it). Now, my UI consumes quite a bit of resources because of some heavy calculations, but this thingy beats it in just few minutes:
And yeah, even after you kill it, it keeps rising from the hell as a pesting zombie. What a marvellous decision to improve your users experience, Opera!