Hi Daniel,
we had a similar problem with the font "Courier New". We opened a SAP incident and got the reply that this font is not delivered with ADS. The problem does not occur for all forms with this font but in our case some chinese characters caused this issue. The resolution proposed by SAP was the following:
Downloading "Courier New" font from SAP note 1817893.
Upload all *´.ttf files to /usr/sap/<SID>/SYS/global/AdobeDocumentServices/FontManagerService/fonts/customer
Ensure <sid>adm has read permissions on these files.
Restart AS Java system.
The exception error was gone in our case but the format of the form was destroyed. The strange thing was that the error did not occur on all ADS servers in our landscape however all servers where on the same patch level.
Let me know if the solution will work for you.
Regards, Martin