[tor-relays] TOR Exit Relay Bandwidth Drop

I run a fast tor exit relay. It goes to 100MB/s easy after a few days but every 2 weeks something happens (no hardware/network issue on this node locally) and the tor bandwidth drops down to 1-2MB/s.

Then I have to stop the tor service and start it again after a couple mins.

Most of the times, I am not aware this has happened and the exit relay then takes 10 days to start pumping full bandwidth again

The server runs Ubuntu 18.04 LTS

Seeking advice from some big brains here, thanks.