Spot Gaussian blurs gain a halo when edited or copy-pasted

[jimteal]

Editing legacy artwork and if this gaussian blur is breathed upon, it freaks out and gets this halo around it. I know this has been a problem for... a while. Years. But I expected it to be fixed by now so I'm creating a new topic in hopes that it gets addressed in some future update. Our workaround right now is to try not touch it, but that might not be possible forever.

Here's what the legacy art looks like.

Opening the Gaussian Blur dialog to take a look at the specs.

Blur gets this nice new halo around it. It won't go away... ever. Best bet when this happens is to close the file without saving and reopen. 

[Monika Gause]

Just how old is the artwork?

And in which version are you opening it?

WHat are we looking at?

A background object in the spot color, then several gradients and then that gradient mesh in the same spot color? What is it?

[jimteal]

It's a spot color element with a Gaussian blur on it. I know it looks more complicated than that but I promise you it isn't. I can replicate the issue with any simple shape.

Using Illustrator 28.7.5.

[jimteal]

Draw a shape with a spot color fill, on a background with the same spot color fill. Add a gaussian blur and you'll get this halo.

[Ton Frederiks]

You may try Darken blend mode.

[Monika Gause]

OK, I'm getting it.

I don't know how Darken will work with different colors, so I would try and apply an opacity mask.

And then of course report it as a bug.