Don't know how you are doing this, but I decap and resize first, not so much as to sizing, but the decapping aspect. I do this because I anneal by firing up the lead pot, getting the alloy to about 560 degrees, and then dipping the cases into the alloy to the point where I want the anneal ring. Wait until my fingers start to get hot holding the case heads, and then drop them into a bucket of water at me feet.
Be careful not to get water in the lead, or any other impurities.
But you may have a better way.