I had something similar happen once with a very large pdf export. Since then I break my construction documents into smaller sets...floor plans, elevations, etc. each with their own LO file. This really helps with organization and helps if you only need to send out a couple portions of the specific set.
That said, the way I fixed the problem, was a did a "Save as" to the file to preserve the original copy. On the copied file, I removed the pages that were problematic. I then inserted blank pages in the locations of the sheets removed. I then copy pasted from the original files all the page specific information to the new blank sheets. This doesn't take very long and is worth a try as it worked for me. After that, I never tried to make my LO files typically more than 8 sheets max.