It's true that the military action on June 21st would have clarified things for everyone, but saying it triggered the 'No' resolution for June 19th and 20th feels a bit like mixing things up.
The markets for those earlier days would have closed with a 'No' simply because nothing happened on those specific dates, much like how you wouldn't get a refund for a cancelled event if you hadn't paid for it in the first place.
Perhaps the later event gave a sense of closure, but the absence of action on the 19th and 20th was already a resolution in itself.
It may be more accurate to view it as the earlier dates resolving independently due to a lack of activity.