Import psd elements with transparency then see the contour when printing

[Curieux75]

Hello, I don't know how to deal with that : when I import psd documents (CMYK) with transparent background in my Illustrator file (CMYK), sometimes, depend of the printer, I can see some kind of contour, or strokes when it comes the printing. My solution right know is to import a psd document at the same size of my whole Illustrator document to avoid this. But it is not really convenient.
Can you please help me ? Thanks.

[Monika Gause]

That might be a couple things:

1. There are actually white pixels at the borders

2. flattening stitching

3. The YDB syndrome https://creativepro.com/eliminating-ydb-yucky-discolored-box-syndrome/