Unfortunately after thousands of miles of all different types of riding, on all sorts of different bikes, I broke a spoke. I guess I shouldn't be that upset considering it was my first, but this one was a bit strange so I'd like other mechanics' thoughts on it. (I work at a shop as a mechanic)

Broken spoke in question was a rear NDS Sapim CX-ray. The wheel is a Powertap G3 to a Pacenti SL23, 24h, 2x both sides, all CX-Rays. I've built many wheels and the last few years have been racing/training on wheels that I've built. Last year I trained/raced on a set of A23's, same hubs, but Sapim Lasers (essentially a non-aero CX-Ray). I rode the crap out of those and crashed them twice. The rims bent slightly but even still I trained on them all year and into the Fall with no issues.

The wheels I'm riding now were just built about a month ago and only have a few hundred miles on them. The rim is arguably nicer than the A23 (welded seem, a bit deeper/wider profile) and overall I was very pleased with the build.

This brings me to today, where after about 30 miles of riding out of nowhere I brake a spoke. I didn't hit anything and wasn't hammering on them. Also worth noting is that I weight 140-145 lbs, which is well within the weight limit of a 24h rear wheel. Also, the spoke broke right at the bend.

Like I mentioned, I've built dozens of wheels and all of the wheels I ride now I've personally built. The spoke lengths are all right on and the tension/true to my knowledge was right on.
My only guess is that there was some uneven spoke tension which put too much stress on that one spoke. Maybe it was too little tension, but I know these wheels are sitting at the correct tension.

Any help or suggestions at all would be very appreciated! I replaced the spoke already and things seem fine. I'm hoping it was just a one time freak thing and won't happen again.