Major platform problems yesterday and today are making it pretty difficult to troubleshoot anything right now:
I think you’ll probably have to wait until that all settles down and then check and see if the Hue is still having problems.
As far as reliability/stability, that is not SmartThings’ strong suit. It is a very flexible, powerful low-cost platform, but they make changes all the time, and things can get a little rocky.
If stability is your top priority, you may want to look at other systems instead. Every system has pros and cons, and different ones will work for different people.