An electoral college winner losing the overall popular vote has happened much more than once. Florida was more or less a coin flip that landed on its edge and stayed that way.
It's happened four times, of which the first went to the House to decide, and the 1876 and 1888 were in a time of widespread corruption, but nonetheless it's still very rare, especially in the modern day, and I wouldn't expect it to happen again in our lifetimes.