Hey Dan,
I have the same issue with no colour in my images. I'm new to astrophotography so this could be an issue on my behalf however, I also find that when I include flat files I have what looks like a bayer sensor pattern on the flat files in the astrohphotography stacker as well as the final stacked image even though the JPEG version of the flat files are all white. Is this a software issue or my own error? Additionally, when following the youtube video by James Ritson titled Editing astrophotography images (Affinity Photo) I am unable to bring out the detail of the galaxy through the curves tone stretching process, rather any adjustment just lightnes the whole image quite drastically. Is this due to the files being in black and white or again my own error?
I have uploaded a folder named "givnik_fujifilm raw files_afinity photo" to the above dropbox link with a set of photos I took of the bodes and cigar galaxy. This includes light, dark, flat and bias frames. My camera, lens and settings were as follows:
Fujifilm X-T3 camera
Fujifilm 100-400mm lens
Raw uncompressed RAF files
Thanks and look forward to this issue being fixed.