I am troubleshooting a DHCP relay issue with the DLR and have found this KB article useful in identifying known issues with NSX 6.x for vSphere. The article get updated periodically.
It turns out we ran across a bug that should be fixed with version 6.2.3.
Source: VMware KB: Trending issues and important information regarding VMware NSX for vSphere 6.x (2131154)