I have encountered an instance where I've started a new world (lots of mods) got the purple decal book....but, the book is empty. Please let me know if you'd like to explore it further.
Regards,
~B

Things improved...a litte. I now have purple blue-prints in the purple book. But no decals on them.... :(

I see now why I am seeing no decals. I have 'Show Decoratives' disabled.

Even, so...still no access to the decals themselves. Deactivating for now (at least while I'm back to MP).