Happens to me all the time too. When a decent domain expires, and nobody bids, there are often tons of other people all thinking they’re going to be able to buy it as a closeout.
When I keep refreshing continuously, I’ve often seen the name appear, and then I refreshed again by accident, just to see it gone a second later.
One time I was waiting for a nice name to expire, and I thought to myself it is too good to be true that nobody else is bidding on this name. Since I thought that somebody else would be able to snipe it before me anyway, I placed a bid 3 seconds before the auction would have closed, just to see what would happen. 15 other bidders immediately jumped in and started bidding on it (within seconds, so they were all watching it), and the bidding frenzy attracted a lot of new bidders as well, and the name went for high $XXX. If I had not placed that bid, some lucky guy would have gotten it as a closeout.