It might just be limited for that run. obviously I don’t know how or where the book is being printed and it could be a completely different situation, but where I work a full colour book like this normally has to be booked in to print a few months in advance because of the time it takes, and printers normally have a capacity of how many full colour titles they can print at once. If she’s using a printers that prints for other publishers, they would have had to fit the original print run and any future print runs into their schedule amongst all the other titles printing.
Hopefully it’ll be back for those that want it, just might take a few weeks.