Artifacts Problem on illustration

[augustinl89391933]

Hi, just got a whole font rejected today because of the "Artifacts problem". My question is quite simple: How can I fix this and in my case what does it refer to ?

Thanks !

Here's an example:

[uk-BPP]

to me it seems as if adobe quite often can not tell the difference between artifacts and natural structures. I got a lot of pictures rejected, where there was a certain structure in a surface like a on concrete wall or tapestry