I'll take a look at this...
Are you using spell ids > 45000, by chance?
EDIT:
Actually..does your current code include this?
https://github.com/EQEmu/Server/comm...0416c484d87f37
If pages 60 and below are all full, this may be the issue.
Try scribing spells on the lower pages to verify .. this should affect all pages, not just the new ones.