Did you recently buy a new ball or have your old one re-drilled? If so, you could have your span wrong a bit.
If not, then it is definitely something you are doing now that you didn't do before. Figure that out and you will get back to throwing the ball like you want.
P.S. With me, sometimes when I get my feet ahead of my armswing, I muscle the ball and my hand goes around the ball causing the effect you are talking about. Might look into the timing thing if all else fails.
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