Is there some kind of screw holding the handle onto the valve? I'm thinking about the handle for one of the hoses at work. It has a small square peg with a threaded hole in the middle on the faucet side, the back of the handle has a square in it with the hole, we are missing the screw. If the screw is loose, it's possible that the handle was backed up off far enough to not spin the valve the first time you moved it. And you have unintentionally re-indexed the handle on the valve. If this sounds like what your valve looks like, then just reindex it the right way and tighten the screw.

If it is not like this and it doesn't seem like there is any way that the handle could spin without the valve moving, you might want to replace it even if it's not leaking. That doesn't mechanically make sense how that could work, that might cause you problems at some point, like the next time you need to use it.

It's also possible that it's not fully turned on in this situation. Like it could be about 3/4 of the way open, enough to give you the water pressure you would expect out of one or two faucets at a time.