This issue is prevalent in NSX-T versions below 2.5.2, and the symptoms may manifest in different forms. Here are some examples.
All the TCP/UDP traffic gets dropped at Tier-0/Tier-1
or
NSX-T Load balancer stops processing all the traffic
or
The HA state on the Edge shows as Unknown.
ICMP traffic works fine
Issue is seen only after traffic burst
Upgrade the NSX-T to 2.5.2 and above.
NSX-T 3.2.0 and above has some additional enhancements.