You can find clues in the MPU2 Fault Status Register value (0x0E080010), bits field [5:0] is 10000b which means "Supervisor Write Fault" is the cause of this access error based on the description in MPU user guide. And bit field [23:16] is 0x8, so master AID 0x8 (CPU0_CFG) is the master which generates this Supervisor write fault.
Then if you look at the PROGn_MPPA register value (0x03FFFCE4), bit field 4 "Supervisor Write Permission" is 0b which means "Access not Allowed". And you enabled AID 0x8 in MPPA (bit 18) to check for access permission.
So probably you should set 1 to "Supervisor Write Permission" bit in PROGn_MPPA register(s) to enable the access for all AIDs which are enabled.