Quality of AFR valve springs?

Are the valve springs (AFR part #8015) that came with my AFR165's (AFR part#1402) with the 8032 spring upgrade poor quality/junk/known to break/etc.? I had one break on me not long after I installed the heads (about 100 miles). I had taken it easy on the engine, not revving over 4000 ever (rev limiter) and when it broke, I was just cruising along, not beating it or anything.

Should I get better/different ones?

Thanks,
Rick