The missing piece of information is that the Navigation Tree is in Standard View, and I would bet tzr916 is in Theatre View. In fact, he would be in Display View, since he is watching something and pauses it.
Aside from that, there is definitely a CPU usage increase both in playback since early MC23, and during the pause of video, and it is not related to any activities reported by MC in Reporter.
BTW, a "Sorry Jim I don't understand" may get better responses and attention to the issue than "What are you talking about?"