so i am kind of new to making chocolate. I have been using a chocovision delta for about about 2 years to make one ounce square bars. one of my bars is a mocha crunch bar. 55% dark chocolate with powdered local roasted coffee then I sprinkle the back of the bar with crumbled biscotti. its good. about 25% of the time i get an odd blooming. its not a sugar bloom and its not all the time and sometimes a bar will bloom when the bar right next in the mold will not. 

does anyone care to share some tips for making coffee chocolate bars?

Nothing special required here.  Make sure your chocolate and coffee are about the same temperature when you add the coffee - if that's not it, then chances are you're not tempering your chocolate as well as you think you are, or you've got humidity issues.