Thanks for the details, @hugh!
It is very strange that System UI crashes. That could be a bug on your type of phone. Could you update to Hue Essentials 1.12.5 on Google Play and try again? (If you do not see this update you need to sign up for beta testing which can be done on Google Play when you scroll down)
Unfortunately, I am not able to reproduce the issue yet but I hope that this update solves the issue for you. Sorry for the inconvenience. Please let me know how it goes after the update.