Christmas Light Rules w/ Scenes & Conditions

I've read through several related posts but don't understand one point of my new rule.

I've created a virtual switch called "Christmas Mode" and I've created & captured two scenes; one for Christmas devices and non-Christmas devices. I've also modified my Sunset rule to turn on/off the particular scene that is applicable. Based on one test so far tonight I think the code works as expected.

The odd thing is that, at any point after sunset -15, if I press the Christmas Mode virtual switch on or off, the scene responds accordingly. I don't understand this behavior. Can someone please explain?

Thank you!

Tried again next day to trigger scene by changing state of virtual Christmas Mode switch and did not observe the same behavior. Odd.