Please confirm that the firmware has been upgraded to 2.0318 or later with Bootloader V2.05 according to the technical bulletin.  TB2202_Flex-6 and MC6N update.

The Bulletin was distributed on 9th December 2022.

After installing the update, the old 2.0315 can be re-installed and the Flex-6 will keep the new bootloader V2.05.  This will solve the E09 problem.