The SNMP OID 1.3.6.1.2.1.4.22.1 (IpNetToMediaType) on VDX platforms only reports ARP entries within the "mgmt-vrf" vrf but not the ARP entries within the default-vrf (global) irrespective of the VRF that the VE interface you are querying belongs to. That is, if you query the management IP (which is in mgmt-vrf) or a VE IP (which is in default-vrf), VDX will return only ARP entry within the mgmt-vrf for OID 1.3.6.1.2.1.4.22.1.
In order to obtain the ARP entries for the default-vrf (at least for VDX devices), it is needed to poll the OID 1.3.6.1.2.1.4.35 (ipNetToPhysicalTable). This OID is listed as supported in our NOS MIB reference manual (http://www.brocade.com/en/backend-content/pdf-page.html?/content/dam/secure-external/product-guides/brocade-network-os/7-1-0/nos-710-mibref.pdf). OID 1.3.6.1.2.1.4.22.1 (IpNetToMediaType) is not listed as a supported MIB for NOS in our MIB guides.
