It clouded or went solid
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What is happening
Natural waxes and the more saturated fats in the oil come out of solution as the temperature drops. They go back in as it warms, with no harm to the oil at all. Different oils do this at different temperatures, so a blend can cloud partially and look worse than either component would.
Unfiltered oils do it sooner
Filtration removes some of the material that seeds this, so a deliberately unfiltered oil clouds at a higher temperature and more visibly. That is worth knowing when you are choosing between filtered and unfiltered for a product that will spend a winter in a shop.
The answer is the label and the shelf position
A line on the back panel saying that the oil may cloud when cold and will clear as it warms turns a complaint into a sign of authenticity. Leaving it off does the reverse. This is the cheapest fix in the entire property.
Where it does indicate something
Cloudiness that does not clear when the bottle comes back to room temperature is a different question, and so is cloudiness in a bottle that has not been cold. Both are worth investigating rather than explaining away, particularly in an infused product.
It is not a reason to refrigerate
Cold slows oxidation, which is real, and it also makes every bottle in the cabinet look wrong and go thick. For most oils the better answer is a cool dark cupboard, which is also what you can realistically ask a buyer to do.
It can also tell you something about the blend
If a product clouds at a noticeably higher temperature than it used to, the composition has changed, which usually means the base oil did. On a bottled product that is a sourcing event you may not have been told about, and the bottle noticed before you did.