I do not know what causes this, but sometimes if the game has been running for an extended amount of time(multiple hours) The UI graphics will break. The menuscreen lacks it's usual graphics and is almost completely white, ingame the empire vault and all shops lose their graphics and become almost completely white. E.g: the chest images etc.. in moe's remain but everything behind it is white. for the vault all the items remain visible but everything behind it is white. Restarting the game seems like the only "fix". I forgot to take a screenshot, but should it happen again I will include it here. Hopefully this is a decent enough explanation in loo of a way to reproduce the issue, I have heard from other players that this has happened to them too.