Weird artefacts when printing outer glow effect

[#1]

Hi,
I am using Illustrator 2020.
I have an outer glow effect  applied to a shape and also a drop shadow multiply effect to get a neon effecr.
In Illustrator everything looks great on screen.

When exported to a Pdf there are white artefacts.
When printed no matter if out of AI or Acrobat there are black artefacts. Can't solve this.
Anybody have an idea? Image 1 is the smooth display in AI and image 2 the artefacts in Acrobat when saved as X1-a 

I have set the screen resolution in document setup to high resolution because this needs to be printed

Thanks in advance

[#2]

Hi,
I am using Illustrator 2020.
I have an outer glow effect  applied to a shape and also a drop shadow multiply effect to get a neon effecr.
In Illustrator everything looks great on screen.

When exported to a Pdf there are white artefacts.
When printed no matter if out of AI or Acrobat there are black artefacts. Can't solve this.
Anybody have an idea? Image 1 is the smooth display in AI and image 2 the artefacts in Acrobat when saved as X1-a 

I have set the screen resolution in document setup to high resolution because this needs to be printed

Thanks in advance

[#3]

Here is a photo of the artefact when I am printing

. 

[#4]

So just in case, anybody has the same problem. I couldn't solve the problem and decided to import a PSD file with an outer glow element and transparent background.

Solved the artifacts.