I have an idea as to what is going wrong, but I have no idea of verifying it.
When looking through the logs I found that when it tries to start up the executable it does so with the following parameters.
x/x/x/_retail_/Overwatch.exe with args: -uid prometheus, pid: 19340
Based on when you start up other games it looks like this:
x/x/x/_retail_/WoW.exe with args: -launcherlogin -uid wow, pid: 23888
Pretty sure the name Prometheus is not a game and was added by accident and should probably have been Overwatch or OW or the like.