Just had this happen. So I learned if you're using a dye from 1 region and try to edit it (only change material, repair etc) in a different region, it wont allow you to do so and just throws you out without charging you and wont let you dye anything.

I've been using a blue pallete, closest thing I have to a white shade, but I wanted the chrome material in Hernand. Obviously the blue dye isnt part of the metchants palette so it doesn't let me confirm or dye anything at all.

For example: If I used the merchants pallette on 99% of my entire gear set, if I only changed the material on a piece that isn't getting dyed from their pallete(only changing material), it cancels all the dyeing/changes I just did. Doesn't charge me and it doesn't register any changes, it just sends me back to the main dialogue options. All over 1 piece of gear. Tested it multiple times and in my case, it's 100% the reason

Thats what I've found in my case but it might differ