I would first try a battery pull, leave it out for a few minutes (if you haven't already). If that didn't work, you could try clearing all data/cache for the apps you're having trouble with.
I'm just randomly guessing it may have something to do with your contacts and how they are shared between the 2 apps. You might check to see what "type" your contacts are as that can vary across phones and I don't know yours personally. On many android phones, there are what are called "Phone contacts" and/or "Google contacts". If perhaps, you have a mixture of the two, it may behoove you to make them all the same variety where Google contacts are preferred because they will always sync back to the phone per your Google/Gmail account if anything bad ever happens to the phone and you have to factory reset or replace.
Which leads to my final thought on how to fix...a last resort factory reset. Not that big of a deal really but you'll lose downloaded market apps and their data and the various settings you chose when setting up the phone. In your case, with a newer phone, it may be less an issue since you haven't had time to amass tons of apps most likely and a revisit to the market can get them back easily, just make a list beforehand if you go that route.