As usual, you can't do anything about it until you know what it's called. So what IS this?
The group of icons was selected, and then dragged by clicking on new folder 2. Notice how there's a gradient fade effect, so the further away in the group from the click, the dimmer the icon.
For contrast, here's the same group, same drag attempt, but the icons just happened to be a few pixels closer together. The desired behavior:
Notice how there's no fade gradient at all. The being-dragged group is a little dimmer, but all icons are equally intense. The only difference is the icons are closer together. So clearly, there's some threshold somewhere, that if a selected group is more than a certain size in width (or height, btw), the fade gradient is used when dragging. Less, and the icons are not faded.
I would dearly love to turn off the presence of the fade gradient.
Now, I know the controls at display properties; appearance; effects; "show window contents while dragging" have some influence over this. Sadly, if you uncheck that option, the icons in a group are not rendered at all, you just get crummy outlines. Not to mention, it also does the same thing to window contents, which is after all what the option is nominally about.
With no name for this, it's impossible to get anything useful from search engines.