First of all, please check SAP notes below and some articles which may help to fix normal issues in adobe forms processing.
Besides normal ADS configure/ customized code issues, sometimes the PDF driver program got return code '02' of 'SYSTEM_ERROR' when trying to generate a customized Adobe form. But this system return is a little bit too blurred which may not help to figure out what's the root of this system error.
Just debugging this process and finding out maybe this subroutine ''Create_output_current_form' is a good place to catch the details of system errors during Adobe form generation.
- FUNCTION 'FPCOMP_CREATE_PDX' at include program LFPCOMPFRM.

Here the object LX_ERROR contains the exception details much more clear than the return of the Adobe form function module!

Here for this exception, I get the below details from CX_FP_RUNTIME:
TransientException:
A problem was encountered with the results:
RenderResult array is null.;
[Error Log file "DateXXXX_SAFP_XXX_Filename.pdf"
written to /usr/sap/XXX(depends on system settings)/SYS/global//AdobeDocumentService
I don't have enough authority to access mentioned AL11 file path. This tracing log file may help but I can't take it in even I have to authority
😄 cause it could be like this:
at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.runServlet(HttpHandlerImpl.java:XXX)
at com.sap.engine.services.servlets_jsp.server.HttpHandlerImpl.handleRequest(HttpHandlerImpl.java:XXX)
at com.sap.engine.services.httpserver.server.RequestAnalizer.startServlet(RequestAnalizer.java:XXX)
Btw, here's one
article from Jerry Wang that mentioned how to get this trace file during debugging. Unfortunately, set parameter 'FPTRACELEVEL' as '04' at the production system can't be reflected at the value of '_adstrace' in the method CL_FP_PDF_OBJECT~EXECUTE_INTERNAL. And why can't have 'save to local file' options at my side... authority again!?

Basically
from my own experience, if these adobe forms have been generated correctly even just once, those kinds of render exceptions are most likely caused by the contents of adobe forms instead of adobe forms themselves!
For my case, here's the full picture:
- 1, Some finance document has custom logic to collect comments from user feedback emails;
- 2, One customized program will generate an Adobe form with document details and those comments as well then send out;
- 3, Some feedback emails are not plain text but rich text instead which contains some special characters that come from the user's email signature, etc. Then it leads to rendering errors during adobe form processing.
So please check special characters at all inputs tables/structures at the function module of your abode form FIRST when encountering a system error at Adobe form processing.
Added at 2022 Sep 13
1, Function module of Adobe form like '/1BCDWB/SM00000001'
2,
FUNCTION 'FPCOMP_FORM_END'
3, Routine finish_form& create_output_current_form inside FPCOMP_FORM_END

4, check this p_document
-xfd.

5, Unfortunately, the output XML file doesn't contain everything, seems to be truncated~
Anyway, find special characters like & < > ' " at input parameters of FM of adobe forms.
Check my updated blog
here.