Attached a screen capture.
I have a flex box div set as a symbol (see product search bar). If I move into preview mode, the child elements go into a stacked arrangement and will not go back to original layout. Saves fine and published fine but stacks in design mode. I have to jump out of the designer and back in to see the intended layout. Seems like a bug but maybe is a setting I’m not seeing? If I remove the symbol feature, everything seems to be fine. Leaving as a symbol for the moment.