Why I can't use dark theme in Manjaro?

I was using Chrome for a moment in Manjaro. My theme was Adwaita dark which I chose from Tweaks. Suddenly, I noticed my theme was changed for no reason. I had updated my system 4-5 hours ago. When theme automatically changed something shown ~ I guess. It was written use gnome. But, I am using gnome also. I don't know if it was an error. When I try to change my theme again. It is automatically changing to light-theme. It's first time I have faced this kind of error. Why I can't use dark theme?

Magically, I can use dark theme again. I didn't do anything. Yesterday, I had faced the issue. Then, last night I had updated my system. When I turned my laptop on today, I saw dark theme is being used. I don't know what's going on.

Actually, the theme changes automatically when it's 6 AM than, it's change to light theme. When it's 6 PM then, it's change to dark theme. How to stop the behaviour?