Colour swatches don't match

[houseofdeadleg]

In a CMYK document, if I go to the Greys palette and select Black, when I double click the swatch it shows the colour sliders with CMYK values 0 0 0 100 as I'd expect. But if I then switch to the colour tab it shows the values as 72 68 67 88. If I then uncheck the "Lock Colourspace" icon and do the same thing, it shows RGB sliders with 0 0 0. 

If I apply the Black swatch, why does it show differently in the Colour tab?

Edit – I've just tried creating a new global K only black swatch and applying it to some text, but after export the text in the PDF is showing 72 68 67 88.

Edited August 29, 2019 by houseofdeadleg

[Alfred]

Please see this post:

 

[houseofdeadleg]

Hmm, that all seems rather counter-intuitive. Even after creating my own swatch set using only black, and applying that to the document copy, after exporting the text is all a rich black, not just 100% K. I've tried various export settings, but can't get the expected output.

I've made quite a few documents in Publisher recently, but unless I can resolve this I'm going to have to go back to InDesign for the foreseeable future, I can't afford to spend time working out workarounds and getting unpredictable outputs. Which is a shame, as using Publisher is largely much more fun then InDesign.