Friends,
I think there is a lot going on there that we don't know. The bow did not break as she got to full-draw, but rather when she released the string. I suspect it is an old bow designed for B55 strings that is now set up and probably shot many times with a new low-stretch string. She was also having trouble holding at full draw and the nock might have slipped some. I don't think we can conclude too much until a lot more detail is known.
I had a Bear Take-down break a limb on me. It happened as I was approaching full draw with the third or fourth arrow in a 10-arrow quiver. I found that the screw that held the latching lever for the limb clamp was preventing the latching lever from fully engaging. I fixed it the riser but needed new limbs. When I contacted 3-Rivers they told me they would cover it under warranty but because I was so short of time I just bought replacement limbs and went hunting. The 50# Bear Cheyenne if bought as a back-up is SWEET!
I don't think we can infer anything about that bow without a ton of additional detail that isn't in the video.
Best Regards,