Ah, 2:14 is the top of the pine... yeah, that's the knives hitting the butt as I'm working the feed bar to fold some limbs.  At 1:45 it blew some vapor dragging the knives trying to get something in.  If I think of it, I'll chip another similar tree, then shut it down and check the temperature of the knives.  
Watching (and listing to) the video, I know it's not reversing in the video. I know the controller has a reverse function but one of the things the 720 is a manual control valve unlike the rest of the lineup with an electric valve and reversing autofeed.  I'll have to check.  
ETA, before I hit send.  I checked the schematic and the 720 doesn't appear to have the plumbing to have reversing autofeed.  I stand corrected!