Magazine in Book module doesn't allow 240 pages

I'm not sure if this is a Blurb issue or Adobe.  I have posted a similar question on Blurb's support site.

Creating a Magazine with 240 pages.  Blurb says this is the limit for a Magazine.  While creating this magazine ( and have saved it) it will let me put 240 pages in the magazine.  But, once I start adding images to pages greater than 215, then for whatever reason close LrC, then later launch LrC and go back to the Book module there are only 215 pages in the magazine.

The images that were placed on pages greater than 215 indicate they have been used on a page, but those pages no longer exist.

I thought I had messed something up, so to get rid of the indicator that they have been used in the book I had to remove those images from the collection and then re-add them.  Otherwise if I added pages after 215 and used them again they would indicate they where used on two pages.  I then added more pages and images.  But if I close LrC and come back to that book/magazine the pages after 215 are now gone again.

I have made quite a few books and magazines with this module, but I don't think I have made one with 240 pages before.

LrC 14.2

Win 11 24H2 (OS Build 26100.3775)