Memory abort occurs after ISB instruction during execution of enable mmu at el3

HI Team,

We are encountering a synchronous data abort (memory abort) immediately after executing the ISB instruction in the enable_mmu_direct_el3() function in TF-A BL1 image.  We are using neoverse v2 reference design. How we can find out the root cause of this issue. The following is the reference snippet code. 

<enable_mmu_direct_el3     MRS      x4,SCTLR_EL3
<enable_mmu_direct_el3     MOV      x5,#5
<enable_mmu_direct_el3     MOVK     x5,#8,LSL #16
<enable_mmu_direct_el3     ORR      x4,x4,x5
<enable_mmu_direct_el3     AND      x5,x4,#0xfffffffffffffffb
<enable_mmu_direct_el3     TST      x7,#1
<enable_mmu_direct_el3     CSEL     x4,x5,x4,NE
<enable_mmu_direct_el3     MSR      SCTLR_EL3,x4
<enable_mmu_direct_el3     ISB
<enable_mmu_direct_el3     RET

Register values when issue occured.

ESR_EL3 : 0x0000000086000014
SCTLR_EL3: 0x0000000030ed183f

 FAR_EL3:0x0000000000010200