Hello Victor
You probably have changed a variable or internal table in the enhancement and the data has become inconsistent. This can cause the cancellation of the delivery change in the update module.
I recommend you to check the error in SBWP. The documents with terminated update remain in the Business Workplace with the description of the cancelation reason/point.
You can also debug the update module when saving the delivery, turning on the "update debugging" in the debugger (menu Settings->Change Debugger Profile/Settings).
If you're still not able to find the reason for the error, please share the code in the enhancement and also the details of the error recorded in SBWP.
Best Regards
Luis Becker