So if you guys didn't know, currently if you vault written books it wipes the signature and writing in it. Is there any news on fixing this bug/problem/glitch?
I don't know if they'll fix it, makes book sales harder. My multiserver delivery process might be too slow for some people.
I doubt it. Fixing this would likely require a full rewrite of the /vault code and more server resources.
It isn't just the vault either. If you sell books in a playershop they will also be erased, so i would suggest making a backup of all books created. Whether this can be repaired or not is unknown, but someone from the development team will know for sure.