I'm not sure why, but Photoshop CC keeps automatically changing my font back to it's previous font after I attempt to change it to a new one.
Current font in document: Source Sans Pro
Attempting to change font to: Open Sans
So far the only way I've been able to succesfully change the font is to choose something like Rockwell, click off the font. Then select it again and I'm able to choose Open Sans. Considering the fact that I'm attempting to make this change across an entire website design, 10+ pages this is very frustrating. It previews Open Sans when it's highlighted and I've selected the font from the character window but instantly reverts after I click to use Open Sans.
This seems to have been an issue with TypeKit. Luckily I had a copy of Open Sans on my home computer and was able to turn off the TypeKit version I was using at my office.