We have several routers with the last firmware and configuration. We have this configuration
When NMA forwarding is enabled CPU load reaches almost 100%
Investigating this problem we have detected that UDP connections are too high, above 16000 active connections are shown in the status-graphs-connections
We have checked the number of packets sent with wireshark and hundreds of them are sent every single second mostly GPGGA sentences.
Please note that the size of the packets is increasing with each new connection