It's not uncommon in some democracies to require multiple votes for major changes (such as constitutional changes or leaving/entering intergovernmental orgs). And 4 points may be a clear margin, but it's not a large margin, and polling showed an immediate shift in opinion. In terms of the Scots, 62% is an actual blowout. And I'd think it might be enough to overcome the 10 point gap on their vote on independence (pre-Brexit).