After some digging, I was able to actually get a pretty good understanding of their passive (-ish) lift. It seems like there is no vertical actuation of the tall lift at all that is only for the bin holder (it can go up by itself). It looks like there is actually some surgical tubing passively pulling the bin holder down (easily seen at ~30 sec in video), so that it can't "bounce" off the top of the stack while one is being made or when the stack is jiggling around. Also, when 1114 grabs a can, they have to first lift it to the height of 1 tote, which is actually done with the use of their normal "tote lifters" pushing their can grabber up while it is holding a can (at ~25 sec, little spinner is rotating to confirm the "tote lift" being run). It is not clear, at least from the video I can find, how the can grabber is kept at the 1 tote height after being lifted there, but there is a chance that there is a passive 1-way latch mechanism that locks it to (/above) that 1 tote height when the bin grabber is closed (dual use mechanism, can clamp on bins, and engage lift latch). The can grabber can drop all the way to the bottom and miss the latch because the can grabber is always open when it drops to the bottom, and (I presume) was designed to miss the locking level when the grabber was in the open state.
This is all just speculation as to what might be at work behind that beautiful red powdercoat, and it will probably be thoroughly explained when they post their robot poster for SideSwipe.
I am absolutely astounded by the complexity and simplicity that went into this robot, and the level of foresight that was paid to how this game would play out. Intaking fast and being able to sturdily handle a full stack seemed to have been top priorities for 1114, and they were definitely able to achieve them.
Here's the video that I referenced up there (Quarters 8):
2015 - Greater Toronto Central Regional - Quarter Final - 8
(watch in HD for a better view)