save the drawing with ai extension (background problem)

Hi,

I save a shape I drew in illustrator as ai. When I add this shape to a document in indesign running on win 11, the background becomes white. When I transfer the same shape to a document in indesign running on macos, the background becomes transparent just as I want it. There was no such problem before in Win 11 indesign. What do you think is the problem?

thanks in advance