Dear Community,
The problem is the upstream device, due MX still keep retry to connect to VPN registry(dst UDP 9350-9351) every 10s so upstream device still keep that session alive from MX.
The restart MX or modem is force to restart source port that MX uses to connect to VPN registry, it is not a good solutions if under production and VPN concentrator deployment.
So the solution should be check, fix on the upstream device such upstream Firewall, or ISP.
Thanks, BR,
M.MAKARA