Helicopter certification standards must permit RRPM to be recoverable by a "reasonable" pilot and that generally means at least 2 seconds must be available. When flying an incredibly reliable twin, double engine failure possibilities seems so remote compared to being on the edge in the 206 all the time given the immediate consequence presented by the failure of one engine in a single engine machine.....
The recognition keys are the same in all machines, so it reacts just like yours to complete loss of power to the drive train, though apart from the yaw you mentioned, pitch movement is also a key factor. It is really here that individual machines behave individually, some pitch remarkably, some hardly move and have advanced mixing units to cope, some pitch up (rare), some pitch down (more common) and some even change depending on configuration : floats fitted, winch fitted, external tanks fitted or even emergency floats deployed.