If your monitor is correctly calibrated, then it sounds like a Blurb problem.
Contact them, you may find them helpful.
It's possible some of the colors in the artwork are outside the printable gamut. Try downloading the Blurb.icc profile and soft proof the image files inside PS for the pages that have incorrect color. The book printed images may be darker due to your display brightness being set too high. Do you use a monitor calibrator and if so what luminance setting are you using? Also did you upload the book from inside LR using 'Send Book to Blurb' or did you upload the PDF export file manually to your Blurb account?
I printed the worst pages on my Epson 3880 and compared to the Blurb book and my monitor. There was definitely a color problem with Blurb. I contacted Blurb and they offered a credit to resubmit the book. Note that Blurb puts subcontracts their printing to a number print vendors; results may vary vendor to vendor. I did notice that the worst color shifts were for files that had layers; I flattened all the files that had layers and resubmitted the book. The result was significantly better and much closer to what I was expecting
I recently published a book of illustrations generated in Procreate and exported them as psd’s. Because the book was to be printed on a commercial printing press I converted the files to cmyK and used InDesign to layout the book. The color was spot on.
If I were sending the files to Blurb and wanted to use the Lightroom book module I most likely would have imported them first into photoshop, checked the color profile and confirmed that it was sRGB or Adobe RGB and changed it if need be. Then I would save the changes to the psds and import them into Lr. I likely would send a test spread to Blurb before printing the book.
If they are willing to reprint the book, perhaps they will do a test for you?