So, I just in Star Fields, farming stars (of course), but when I was starting a battle, I accidentally exited the Robot Select screen, but I had just enough time to click on the "Start" button. When I clicked on it, the "Back" button had went back to the Star Fields screen, but the battle begun. Resulting in this..
The battle never actually started, it was stuck loading like this.

Ageman Edit: As the user said above, this was caused by the battle being loaded and then unloaded via your fast clicking. It's annoying but not something I can really solve without a lot of restructuring of the code. Unfortunately I'm gonna have to close this thread. Apologies.