VMware has released NSX Data Center for vSphere 6.4.8 and removed version 6.4.7 because of a serious bug.
So if you have already deployed 6.4.7, it a good idea to upgrade if you need to change firewall rules.
- Fixed Issue 2614777: DFW Rule Publish fails if a rule is comprised of two services with overlapping service port/range of service ports
- DFW rule publish fails.
See the full release notes here.