Dacor microwave waveguard cover

After some research (novice here) the waveguard cover in my microwave is arcing. If I purchase a new one and simply replace it is that all that needs to be done or has something else possibly been damaged internally?

Here’s a video of what it’s doing:
https://youtu.be/jNlc6HN7zRw

This is the part I was going to order:
http://www.appliancepartspros.com/dacor-wavegude-cover-66490-ap3395584.html

Thanks!
Shelly