Bug High CPU usage on new UI Default Material

I was playing around with UI backgrounds for a panel, and at first focused on the wrong thing, the UI Default Material. So I decided to make a new material to see if I could get closer to what I wanted. And noticed when having the new material selected, and it's properties showing in the Inspector:

That I started hearing my cooling fan wind up, so I checked my Task Manager and saw this:

The high disk usage is my anti-virus going nuts trying to find what's using up CPU usage.

So I went back into Unity, and clicked on an open space to get the material properties off the Inspector, and Unity's CPU usage went back below 1%.

I'm not sure if this is a bug, or playing around with a new UI Default Material is just a big no-no? Either way, I found that there was no point to having a new material, for what I was looking for. So I'm taking it as a "just don't do that again" moment.. lol..

But I'd figured I'd mention it, in case this is not normal behavior.

 

I'm sorry, I didn't see any plain discussion or bug area in the forums for UI issues. Feel free to move it to the appropriate forum.

While in Editor(Project > Assets) I created a new Material, and in the inspector I changed it to UI/Default. And then my cooling fan started winding up, hence the high cpu usage. clicked off of it to clear the Inspector, everything was fine. Clicked back on it and again fan winds up. I tried multiple times, and was able to screenshot it, from being able to re-create the issue every time.

As far as which toolkits, I have no clue. It was a fresh project(3D Core), and I haven't added any packages or anything. I'm using Unity 2021.1.10f1 Personal, if that matters at all?