High CPU usage several times a day

Running a routing node on a Pi 4B 8GB with an external samsung SSD.
Using tor as per usualt, but also added an external IP to lnd.conf which is a VPS I use autossh with to create a reverse ssh tunnel for port 9735.

Every so often during the day the node becomes unresponsive, various app webuis (including the default umbrel one) hangs.
Upon checking resource usage via ssh I can see that avg CPU usage when this happens hovers just below 5 (htop/uptime reports this).
I see that its always lnd that uses all 4 cores at 99+%.
Further digging in to it I can see that always when this happens lnd.log reports these lines:
2022-06-05 21:56:55.105 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node
2022-06-05 21:56:55.106 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node
2022-06-05 21:56:55.106 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node
2022-06-05 21:56:55.107 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node
2022-06-05 21:56:58.043 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node
2022-06-05 21:56:58.044 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node
2022-06-05 21:56:58.044 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node
2022-06-05 21:56:58.045 [ERR] RPCS: [/lnrpc.Lightning/GetNodeInfo]: rpc error: code = NotFound desc = unable to find node

This line sometimes, not always, comes after some of the above lines and then the node becomes responsive again:
2022-06-05 21:58:00.513 [INF] CRTR: Processed channels=0 updates=124 nodes=0 in last 3m17.024234628s

Any thoughts?

Post logs, not enough info for any guess.

Didn’t want to post the complete lnd.long as I assume there could be “sensitive” information (wallet keys etc) or is it safe?
Any other logs would be needed?