When “Manage through internal network” is enabled, SVM tries to first enable the internal interface(in this case it is 0/2) of VPX and then try to add ARP.
In this case, both the operations are failing because 0/2 itself is not present in VPX
When the VPX was provisioned it’s build was 12.1-63.22 where VPX-always-ON support was not present.
So It had only one management interface i.e 0/1 .It didn’t have 0/2. Later VPX was upgraded to 13.0-86.17 and 13.0-86.102 which has VPX-always-ON support but internal interface is missing.
So it is not possible to enable “Manage through internal network” for this VPX.