This is a know issue affecting Cloud Director Availability 4.x.
Currently there is no resolution.
Workaround:
To confirm you are experiencing this issue, perform the following steps:
If the results for the command are the same for the Recv-Q column for one or more connections this means that those threads are stuck and you are currently facing this issue.
To work around this issue contact VMware Support and note this Article ID (91034) in the problem description. For more information, see Creating and managing Broadcom support cases