Like many oldies, this one might have gone through some bad times, and the juice -assuming that it's an original- might have changed, we'll never know for sure what has happened to it, if it was exposed to the sun or extreme temperatures or anything else.
I have come in contact with Arpège bottles that had pristine-looking yellow liquids that have never seen the sun and were older than 30 years and they didn't have any clouds in it.
Now that one fragrance has a few clouds doesn't entirely, or necessarily mean that it got spoiled, maybe the chemistry inside was playing tricks and they got re-formed. In any case, it depends on the way it was stored and what has been done to it.
Many oldies tend to "macerate" over time, sometimes that changes the scent, sometimes it doesn't.
More likely than not though, it changes the scent. The older the bottle, in general,the more "natural" the ingredients are (and that's a very wide "in general" so don't take it too literally), and thus the chances to change over time are increased.
Maybe the bottle you got is even older than what the seller said it was.
Me, i like an oldie very much, cloudy or non-cloudy. And the older the better!
Hope that helped,