Weird Pathfinder Behavior. What's Going on with my Image Preview?

I keep getting the weird result shown in the first picture when I use minus front with the pathfinder. (The text is outlined and on top of the rectangle.) Notice how the T and U are messed up. In outline mode, though, it looks fine. All of my paths were closed before using minus front. The same thing happens when I build this using the shape builder tool. Does anyone know what's going on here?

Restarting the program and resetting my preferences didn't help. I'm not sure how to troubleshoot this from here.