Tubes sound like a broken lightbulb


So I just bought some pretty fancy NOS tubes from a big online store. I unpacked them and notice they sound like a broken lightbulb 💡 when I handle them. Is this normal? I paid a lot for these tubes Because they were promised to be and test as brand new.

the tubes are Slyvania Jan-chs 6sN7gt / VT-231 2 rivet “bad boy” tubes

thanks for the feedback
andrewkelley
I don't believe any tube, nos or new should sound like anything when you handle them. I would think a call to the store is in order... 
When i was shopped for some rare NOS i was looking for matched pairs or quads, tested by the seller on professional tube tester and by ears too. Blind deal is risky, i hope you can return for refund or replacement.  
I have noticed a few adds lately as I have been shopping for some tubes like yours that a seller or two has mentioned in the add that the tube had the same issue as you have with yours and that it was not an issue with its performance. I did pass on these, so don't know if there was an issue or not and appreciated knowing the fact before hand.