In Bitcoin's protocol (and similar PoW systems), at one point chain might temporarily split in two and two different chains will be maintained up until one outpaces the other and proves itself as the correct one.
I thought this phenomena is not possible in Cardano since for every slot a delegator is already selected beforehand so we theoretically know from which validator/delegator to expect new block i.e. we cannot have two validators creating the same block for the slot. This is what I thought up until watching a video by Cardano's chief scientist who made be doubt my premise (https://youtu.be/nB6eDbnkAk8?t=1563).
I would love to know if I am getting something wrong? From the video it seems he is explaining the scenario that I thought cannot even happen in Cardano's protocol.