image and shapes not scaling properly on word templates

Hello,
I'm working with a microsoft word template. I've added an image (the light grey square) and anchored it in place. I want it's height to be the same as the blue rectangle on which it is placed but I'm struggling to get it to work properly.

Shown in the images below, the blue section is slightly larger than the light grey image. furthermore, when i scroll to zoom in, blue lines appear on the sides and on the top, as if the two shapes aren't scaling together properly.

I'm looking for advice on how to tackle this issue. Any feedback is welcome.

400% zoom

normal zoom