Can you give us an idea of the time-line? How long have you had the bike? How much time passed between the initial purchase and then breaking 4 spokes? Were the 4 spokes broken on the same ride? How many miles were on the bike on the original factory wheel? Where do you store the bike?

I can easily say that breaking a spoke after a rebuild can be attributed to a bad build, but it's hard to understand why you broke 4 spokes on a stock wheel when you aren't that heavy.