Missing font on few pages

Have a workflow that generate multiples pdf document that have an average of 7000 pages each one. There is an special font that will print 25 times per pages, the problem is that some pages replace the font with a generic font.

If I do some search over the document it start fine until page 3000 then on page 3003 it replace the font. Then continue fine until happen again.

Any place to look for.

There is an option in the Output Preset for generic PDFs to Embed fonts.