What gun are you shooting? You may be getting a carbon buildup on the first two shots and then getting some blow backon the third.
I do know from what I have experienced and heard on this forum that some of the breech plugs react different to this powder. I shoot a Knight Vision and the plug in my gun needs a hotter primer to ignite the powder.
I first used Winchester 209s and it would not ignite my charge. I talked to the factory and they told me to use CCI M and Federal 209A primers. I can't find any Federal primers, but did find CCIs. And they work very well, with no more ignition problems.