I have three text nodes and a rectangle. I select all the four then press an arrow button on the keyboard to move, and boom! 2 of the 3 text nodes leave their positions and go to unexpected places

I tried a workaround like this: group them and then move. Yeah it works, but when I ungroup them, 1 or 2 text nodes would go crazily to another place.
Why?
I don't think inkscape is buggy (as there're so few bugs in the bug tracker). So please don't let me change my (good) belief
