Hello,
Thank you for the information.
If the FlexNVM is partitioned for EEPROM with CSEc, the last bytes (up to 512B) of FlexRAM are not accessible.
AN5401 Getting Started with CSEc Security Module

The behavior of FlexRAM used as traditional RAM once the CSEc keys have been allocation is not clearly specified in the S32K1xx documentation. But in order to use the whole 4KB of FlexRAM as system RAM, the program partition command must be launched with parameter CSEc Key Size = 0. This will release the last 512 bytes.
Regards,
Daniel