What I have found is, the light is not automatically turned off at 21:30+ when no motion is detected; I was under the impression it will switch itself off until it receives motion outside the 21:15 - 21:30 time window.
This is one of my rules for lighting. I did it in Rule Machine because the Simple Lighting wasn't quite cutting it for me. I have a virtual switch to disable the light turning on during times we are watching television because the LED lights in that fixture had been interfering with television reception (antenna).
I had to split it into two parts to do the capture. Maybe this will give you some help to fix your situation. It is possible that you could set up a virtual switch to keep the light on during the time you want it to stay on and then have the light turn off when the virtual switch is turned off.
This is the rule that turns on and off the virtual switch: