Saving out PDFs in CMYK colour space, then Opens in RGB

[JENO]

I'm creating artwork in a CMYK colour space, I then export for screens to get multiple pdf files (with my workplaces profile embeded). When i reopen these files to check them, they are RGB. what is causing this? it's incredibly frustrating, imagine it's just a button i'm pressing or missing. Thanks in advance.

[Ton Frederiks]

How do you check them and what PDF Preset are you using?

[JENO]

To check another member of the team opens up the files to preflight really and we are noticing the files at this point are now RGB. 

Screenshots attached. 

Thank you for replying and trying to help me. 

[Ton Frederiks]

Works fine for me with 27.5, but I first needed to create a PDF preset like yours but without the / and : characters in the name to be able to choose it in Export for Screens.

[Monika Gause]

There were issues with Export for screens and saving PDFs in certain versions. Which version are you using?

[JENO]

OH! interesting! i believe we are on 27.3.1 but i will double check this with the team, i'll do some research into those existing issues with Export for screens. 

[JENO]

Also, thank you for taking the time to help me