Hello Alexander,
do you use COMMIT WORK or COMMIT WORK AND WAIT? The standard prgroms usually do the latter. PPF 'At Save' starts the exucution after the COMMIT and it depends on all data being available on the database already. If there was a simple COMMIT the PPF action might not have found its data.
This would be the most plausible explanation in a system where there is a message log and not PPF execution. The good thing is that the interface from EWM to ERP is mostly self-repairing. It collects the unprocessed messages, gets them in the correct sequense and sends them. So it would send you creation at hte GI posting latest.
Regards,
Katrin