Dear,
I have very strange problem which I never had before. I have got standard stock picture (1), with colours converted to CMYK and size changed for printing. During edition in Affinity Photo everything looks OK. When I export it to TIFF or JPG I receive picture with very strange colours (2). I looks that as windows preview, as well as in windows full screen (3).
When I reopen it in Affinity Photo or Affinity Designer it looks normal.
What may be a reason?