My guess would be that the new finish has changed some tolorance in regards to the way the magazine sits in the gun when seated. I can't think of why, because I don't think electo nickle is that thick of a plating, but I could be wrong (and often am). Best advise I could give is to call the company and have them make it right, or get it to a known smith to examine. Sucks for sure.
"There is nothing like the hunting of man, and for those who have hunted armed men long enough and liked it, there is nothing else>" Ernest Hemingway.