Could have been that as well.
I don't recall the brand name of the crimps that I bought, but I did get them from a 'reputable' source and they were not particularly low priced.
Still... live and learn.
They are also meant to be used with high quality crimp terminals like those made by AMP, FTZ or Ancor to name a few. The stuff you buy at Wal*Mart, or many auto-parts stores, does not have a thick enough copper wall and no strain relief sleeve thus it won't crimp down tight enough because the material on cheap crimp connectors is thinner..