"After-images" strange bug in scene view.

I'm experiencing a really strange bug in the scene view with "Shaded" mode on...

I'm a graphics person and relatively new to Unity, so don't really understand what's going on. Honestly I don't even know how to search/google for the problem. I've tried.

Here's how I reproduced the bug in the images:

1. I opened a scene which exists in an existing project. I duplicate it to modify it but keep the old one as a backup.

2. I duplicate a material to just change the image but keep all the settings. (I've tried creating a new one too, problem persists.)

3. Normally I drag the material to an image component (which you can see in the image below).

4. This is where it gets funky. If I use the new material, not only will the entire scene view behave strange. As soon as something changes, an after image is stuck in the screen like in the end of a game of patience.

5. The bug is strangely trigged only if I drag the material from the project to the inspector, but crossing the scene at the same time, as if I was going to assign it directly to something there.

6. Also, if I use the new material, the image attached won't show up but instead be stuck to the old one. Instead if I use an old material (I've not worked within this scene before) everything works fine and the image is changed.

7. Sometimes the bug is reversed if I delete my new material. Not always though.

Thanks for any help.