Yep. Amazing to see how flexible a bar of steel really is, isn't it?
You can relieve the stress yourself, if the piece isn't too big, by heating the up the bar with a torch to red heat and letting it cool. (You don't have to heat the entire bar at once, just work your way along it.) This may not be as good as buying normalized steel, but it will help.
Or you can do as you suggest -- mill equal amounts from both sides, if you can figure out how to hold the piece while you do it!
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