2018 E92A ECM Setting DTC P0700 and U0100

Every now and then I send a remote tune to a customer and he sets DTC P0700 and U0100. I've written thousands of email tunes, but every now and then this will happen and I never seem to have a good solution.

The exact same thing happens even when I start with his original ECM read and manually edit the tables one by one. Sometimes the codes come up immediately after the flash. Other times the car will drive completely fine for five or ten minutes, then the codes will trigger.

Any time he flashes back to stock and everything is fine.

Has anyone dealt with this issue before? Am I missing something obvious?

Thanks in advance!