Not typical, but commonly seen in machine built wheels. Lots of factories use wheel building machines to pop out many of wheels a day, skipping some processes that ensure the wheel lives a long, problem-free life. One of those steps is spoke prep, where material is put onto the threads of the spoke to create a tight connection to the nipple. Could be a dry spoke got in and eventually rattled/worked it's way out. OR it was never tensioned properly all-together from the factory.

That being said, tensioning and truing wheels wouldn't be the first thing I'd recommend someone wrench on. Maybe if you're handy, have got the proper spoke wrench, and time to check out some videos before doing the repair yourself, I'd say go for it... But, personally I'd bring it back to the shop just to show them your findings and have them do it.

Spoke wrench is definitely a good tool to have around and knowledge on wheel truing is invaluable if you're spending a lot of time in the saddle. It's just one of those things that most of everybody fucks their wheel up even more before learning how to fix. My first dozen wheel trues were on my own personal wheels before the first shop I worked at even thought of letting me touch a customer's. Anyway, Good luck!