All colours are black in flipbook

Hello,

I have been using the Dear PDF plugin for the publications on our site since last year and it has been working really well, but I have just looked at one of our flipbooks previously uploaded and all of the colours have gone black (the photos are still in colour). I have checked and this is the same for all of the PDF flipbooks we have on the site. I am not sure how long the problem has been there as I haven’t looked at them for a while.

It is on auto-update so is definitely the latest version. The problem is occurring on both desktop and mobile. Please can you advise? Thanks.

The page I need help with: [log in to see the link]