Hi Thomaso, I created the colour palette in Designer when I set up the job (I made a mood board of images and selected 'create palette from document' and I exported it as a document palette to the job folder).
I import the document palette each time I open this document or create a new document for this job (weirdly, it doesn't retain the document palette within the document). The hang problem happens repeatedly when I'm working on the original document containing multiple art boards (9 of them). But it also happened when I created a new file with just 1 art board and then imported the job's document palette to that new document. I haven't tested adding other imported document palettes to the original file, but I can do that and check back in.
I've uploaded the document palette here.
Interestingly, I'm testing picking colours from the artwork I've created now, rather than the swatches in the palette to see if that will cause Designer to hang. We'll see.
Palette-Option2Tama.afpalette