Was the yield high to start with?
Or better yet, was the yield where it was to start with because of residual stress from cold work?
When you form it you are redistributing the stresses.
We used to do this with wire all of the time, deform it in order to lower the yield. But it only works on materials with high residual stress levels to start with.
The steel may have been too soft, so they cold rolled it in order to get it to pass.
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