I’ve had issues with Hue bulbs not receiving commands before, but haven’t seen it in a while. I attributed it to the sheer number of commands being sent, and the flood of traffic on the network. That being said, it’s not an acceptable answer. And now that I think about it, I execute a Hello Home phrase in my completion actions. I bet that is always sending an off command to my lights which could explain why I never see it. I’ll do some testing, but please let me know if it happens again.
As for the activation time, you are exactly right. I build that string manually and neglected to account for timeZone offsets. I published a fix for it yesterday so it should be right if you look at it now.
I’ve been testing with QA this morning, and we’ve seen a few exceptions thrown when the schedule starts. I’ll keep you posted with what we find. Do you by chance use an Android phone?