So I have run into this issue both in Rule Machine and in the Mode Manager
Basically, if I want a rule to only happen on Mon-Fri, and NOTHING to happen on Sat/Sun, I can't do this.
I'll set my trigger as 9:30AM on Mon-Fri, but then it won't let me exit the screen. I need to tell it what to do on Sat/Sun. It wants me to pick a specific time, but there is an option called "no selection", but as soon as I click that, it reverts back to "specific time".
I had this same issue when I tried to create a "weekend" mode. I had to put in what time I wanted "Day" mode to start, so I clicked off "sunrise" for Mon-Fri. I don't want Day mode on Sat/Sun, I only want "weekend", but again it forced me to select a time for "Day" mode on Sat/Sun.
Here is a picture of a lighting rule that I only want on weekdays... I'm unable to get rid of Sat/Sun