I am experiencing the exact same problem.
I have created a routine via my iOS SmartThings App (the old one). The automation should be very straight forward. I’m not using the motion sensor but I want my outdoor lights to turn on at sunset and off at sunrise.
I’m doing the exact same thing with another automation on another location (HUB) and it works perfectly.
At sunrise when the action is supposed to trigger, I get an entry in the Events Log telling me “UteAv” has secure actions is false.
I have not been able to test robert.haugen’s suggetion regarding creating the automation from an Android device. but I’d still very much like an explanation as to why this problem occurs.
Anyone have an idea?