CFPDF Thumbnail image missing text when non-installed font used in pdf. Options?

[webm...@ojolo.com]

We are supplied a number of maps in PDF format each day, and use CF11 to generate an image of that pdf using <cfpdf action="thumbnail" ...>

Recently the 3rd party provider changed the fonts they use in the PDF.
As a result the generated images now are missing the text which use those fonts which are not installed on our CF11 server.

Does anyone have a process which works to handle this situation on CF11?

We have tried numerous combinations of CFPDF actions to 'flatten' the pdf before generating the thumbnail image, but we had not found a solution that works.

We want to be able to dynamically handle any future font changes, so installing the new font each time is not an option.

[webm...@ojolo.com]

Example PDFs & resulting generated PNG image

Source PDF: https://www.dropbox.com/s/6rt1hduwe7bre22/1052.pdf?dl=0

Optimised PDF: https://www.dropbox.com/s/ajbcask5qu4vz9k/1052_bilinear.pdf?dl=0

Image thumbnail: https://www.dropbox.com/s/p2hgwxfs42qmzty/1052_bilinear_page_1.png?dl=0