I was asking development about this and one of them made some kernel changes and just finished testing them.
Can you review the kernel parameters?
sysctl net.ipv4.ip_local_port_range
sysctl net.ipv4.tcp_fin_timeout
Then reset them like this:
sudo sysctl net.ipv4.ip_local_port_range="15000 61000"
sudo sysctl net.ipv4.tcp_fin_timeout=30