I was trying to retreat my APC, but everytime that I pressed 'continue' it used 1 Energy, but didn't actually do anything. After reloading the game, I went back and for some reason my APC is now at the start place and it still says "towing Artillery". The APC is now permanently stuck as well. Edit; the only thing that I did between moves was using a different tab for a couple of minutes. When I returned to the tab, the Artillery wasn't visible, so I assumed it destroyed and so I attempted to retreat.