Can publish to Mac App Store but cannot run app from XCode

Hello, I've had a problem a while now where I can actually make a Mac OS X production build for Mac App Store and submit it. Review passes and the app works fine for end users. However -- I'm not exactly sure when -- but sometime in the past few months something changed: if I try to run the app from XCode, the top title says "Running app whatever" and then changes to "Finished running app whatever" just a couple seconds later. The debug window never even appears, and it I open it manually there is no output whatsoever. I can STILL build for archive and submit to Mac store without trouble. I think this is some kind of signing issue maybe. The only thing I can think of that may have changed in the past couple months is that my developer membership renewed. In the signing drop down it shows certificates with two different teams. However, I believe only ONE team actually exists. Previously I had to sign up for iOS Developer Program and Mac developer program separately. However, sometime in the last year that changed so there is just the one unified developer program for both. I am wondering if this may be related to the merging of those two programs. Any thoughts or ideas on where to start? Thanks!