I'm going to stop contributing to spoke breakage threads. I piped up last week on such a thread, and found a broken spoke Saturday morning. FWIW, I started keep a maintenance log some 35,000 miles ago on this bike, and this was the first broken spoked I logged. (Replaced it and rode Sunday afternoon, all is well.)

OP's wheel sounds undertensioned to me. I say that as someone who has had to start replacing spokes on three wheels between 500 and 1,500 miles, and after the machine built wheels were properly tensioned and stress-relieved, the frequency of breaking spokes dropped dramatically. The under-stressed spokes have likely fatigued, and may be at risk of breaking in the near future (again, based on experience).

You're really at the mercy of the shop and mechanic if you don't do your own wheel work. By all means ask them to re-tension all the other spokes, balance the tension, and stress-relieve them all. If they do that as a matter of course, you'll get the "OK, we'll do that" head nod -- the same response as you'll get if they don't have a clue what you just asked them to do.