Hi this time I suspect it is Auctiva, I created and listed 18 listings with 8 views of the item in each.
Gallery and header were the same image however the 8 images were selected in file name sequence as on Auctiva 1 thru to 8.
When previewed on Auctiva before saving they appeared as 1 8 7 6 5 4 3 2 even trying a few this sequence occurred say for 4 it became 1 4 3 2.
Does the header and gallery when different appear correct on preview ?
When posted to ebay this twisted sequence appeared there too.
I am going to raise a support on this.