Color in PDF output for press viewed in Acrobat doesn't match on Windows display from Photoshop PDF

[n8turepix]

I'm using a print shop to do offset printing of images.  They prefer output in PDF, but I edit in Photoshop.  I save my layout as a Photoshop PDF and send it to the shop, but when I open the PDF in the free version of Acrobat Reader, the colors shift when viewed on my screen or printed.  This happens with both the original PDF I create and the electronic proof PDF the shop sends me for approval.  The PDF is in the shop's CMYK color space (CGATS21_CRPC6.icc).  I've verified by opening the PDF in Photoshop that it has CMYK channels and the color profile is assigned to the image.  The shop provided the PS color settings and PDF output presets and I'm using those.  They look right to me.  I have tried using both the "No conversion" and "Convert to destination" options in the Adobe PDF Presets and they both produce the same result.  

The interesting thing is that what I see on my calibrated monitor in Acrobat matches the colors that get printed on the shop's press, but they are not correct.  Can anyone provide insight on what might be happening here?  One wrinkle is my environment is Windows 11 Professional for both PS and Acrobat, but the shop is using Macs.  I am up to date on Photoshop and Acrobat.  

Thanks!

[n8turepix]

I'm attaching two screenshots. The first is the print shop's electronic proof viewed in Acrobat Reader, the second is the original image viewed in Photoshop. If the colors survive posting to this forum, notice the sky is a true blue at the bottom center-left edge of the image while the shop's proof is cyan, and the greens are less saturated in Photoshop than the print shop's proof.  

[Bevi Chagnon - PubCom]

There definitely is a color shift between the Photoshop version and the printer's soft proof. This can be caused by a number of different factors:

1. Greens, blues, and reds are notorious for shifting between RGB and CMYK. So many of the millions of colors we see in RGB can't be replicated in CMYK, where they look dull.
2. Converting from RGB to CMYK always produces a color shift. Hopefully it will be slight, but "Shift Happens." Always.
3. When I did professional color correction, I learned from Dan Margulis to measure the color numbers in Photoshop and don't trust your monitor. Knowing the numbers is the only way to guarantee that the color in PShop is accurate, and then is maintained as it is converted to a CMYK PDF. If you haven't read his LAB books or taken a course with him, check out his website at http://www.moderncolorworkflow.com/dan-margulis   Dan is the genius who literally created the field of color correction in the printing industry.
4. Different color spaces in PShop affect color, too.

It's impossible to tell from your screen captures which numbers are correct; the screen caps are from your RGB monitor, regardless of which color space was used in the files.

[Test Screen Name]

"I've verified by opening the PDF in Photoshop that it has CMYK channels and the color profile is assigned to the image. ". You can't use Photoshop to check these things. It converts any PDF you open according to your settings. So if you open a PDF choosing CMYK it will have CMYK. It will be converted to your working space. The only exception is reopening a Photoshop PDF back in PS. You need to be using Acrobat (paid for not free) in your workflow if you want to check these things.