Oh no! Thank you so much for playing the demo and reporting this issue. When you get some time, could you let us know your device specifics (OS, hardware, etc) so that we can hopefully start to figure out what is going on? This is the first we've heard of an issue like this, but we would like to make sure our demo is as stable as possible.
Also if you get the chance and have a little time, you can check out the demo on Steam as well, and see if the behavior there matches too.