According to Josh’s twitter account,
“FYI: I can’t get into details (and, in fact, don’t HAVE many more details), but it was a layoff. I wasn’t fired and I still love Mythic.”
So it appears the Josh has been laid off from Mythic. He also goes on to tweet.
“Quick note, then I’m going offline for a while: WAR isn’t dying. The game is better now than ever before and more goodness is on the way.”
So without more details to go on it would appear that Josh’s roll within the company had diminished. It appears that they were no longer in need of his services, nothing more.
With that said, it appears to me that Carrie is going to take the reigns. So I look forward to seeing what Carrie and her team have in store for the game in the upcoming months. As for Josh I wish him all the best in his future endeavors. 
Vauleen of Volkmar 