Spokes breaking at threads is almost exclusively caused by nipple misalignment. It'll be more common with plain gauge spokes where the root of the thread is the weakest place, at about 80% the strength of the 2mm section.

It's also possible that the spokes were threaded at the low end of the diameter tolerance. That could cost almost another 10% in strength.

Even with these issues I wouldn't expect failures early on, since it's still a slow fatigue process. However, one thing that might cause rapid failure at threads is excess tension. That can bring a spoke close enough to tensile yield that the fatigue process is sped up considerably, or spokes are simply overloaded by side load impacts.

So, before you blame your spokes, take a look at the tensions and see where you stand.