Moving lines with arrows right after copypasting messes them up

Hello again (to whoever from Storyline staff see this ;))

I've made two new projects recently and in the first glance everything were working smooth. But after some time and work done, the bad line behavior comes back. It won't occur on newly created file (I've just checked). But the file I'm attaching is from like 3-4 days.

The lines don't need even to be grouped, you must just grab line with any other object to move it around, like select textbox and line and try to move - the line will go diagonally after moving. When you select just line, everything goes fine.

I cannot think of the possible behavior why is this happening. I'm attaching the story file. Just try to move the line&some other object with arrows or mouse, it will do diagonally. Move the second one only, without any other objects selected, and it will behave normally. And after that, take that second moved line, select it with another object, move and... it will behave normally, it won't go diagonal. I have no clue :)