Colour palettes not picking up

Just got Cubase 10.5 and finding various oddities: if I open a project with a bunch of custom colours and I click the palette icon I get a random selection of colours, not the set I saved. However, if I just create a load of MIDI channels in the project window it does colour them correctly (see screenshot). Also, if I go to Project Colors setup in the Project menu, it displays the correct colour set, I can change the names of the colours etc but they still don’t appear when I click the palette icon in project Window.

I have a vague recollection this might have happened with a previous update but no idea how I got over it, it certainly works ok in 10.05