EB2-EB3 DOWNGRADE I-I40, SOC CODE:000000

[I-485-EAD 0]

Any idea what is the meaning of SOC Code: 000000 in approved downgraded EB3 I-140 from EB2 and 
is there any issue at the time of I-485 or I-485j approval in future ? 
Please let me know if any one had any idea or any suggestions will be appreciated.

EB2 SOC CODE : 15-1132
EB3 Downgrade Approval notice shows: 000000

Thanks in advance.