I am facing different issue, if I ran one payload through sproxy it is rasing an exception and order created but it is not giving any dump but if i execute it through interface dump is generating for the same payload. In the function module TS3R_REMOTE_DISPATCHER due to incorrect customer it is giving dump in case of interface but not giving any dump from sproxy.
I don't know what can be different in your 2 attempts.
But there is:
This is a KBA about FATAL_ERROR with solution. I can't tell more as it's reserved to the clients with a license.