I have problem to blend mod in group's selection colors. is it bug?

I’m using mac, desktop app, ui3.
If I make 2 or more of any shape, then group them, and set the blende mode of color in selection colors, it doesn’t apply and group unselected. It’s inconvenient because the batch blends aren’t set up in my work environment! Somebody help me!

I use mac, desktop app, ui3.
draw any shape more than two, group them, there’s problem about adjust blend mode in the group’s ‘selection colors’ area.
any blend mode not work through selection colors, but it works through individual shape’s fill area.
it is so inconvenience in my workflow! Someone please give me a clear answer to this question.