That can happen.
I bought 2 of the ten turn potentiomers a bit ago.
One turned out to be bad. No continuity of any sort between any of the connections. And by the time I found that, I had no way of knowing who I bought it from.
From now on, I will test them when they arrive so I know which is which, and can do something about them.
It is always possible to get a bad part with the seller not knowing.
I was testing some transistors I bought, to see which ones had best gain.
Need to bend the legs slightly for most of them.
I started to gently bend the last one a bit, and one leg "broke".
Like it had been partly nipped.
The seller has replaced it with no trouble. Very good Seller. Anyway, always a good idea to test parts before soldering them in place..