Instant Domain Search has these glitches every once in awhile when they show domains as available when they aren't. If you follow the link and try to buy the domain- you won't be able to. Available 3L .com are like unicorns. They don't exist.
With respect, my first thought was like many above - it was actually an IDN. So if that had been the case, it would have been a waste of money, especially if it was aftermarket. We didn't know the full story from the OP so with the rest of the details, it was clearly a glitch.