Restarting the bn on a network before bc launch shows a bunch of `WARN Error processing HTTP API request` messages

[remyroy]

Description

It seems like restarting my beacon node service on a network that has not started the beacon chain genesis yet makes the beacon node process spew a bunch of these WARN Error processing HTTP API request method: GET, path: /eth/v1/node/syncing, status: 500 Internal Server Error messages.

Version

Unstable v2.1.3-e4fa7d9 - https://github.com/sigp/lighthouse/commit/e4fa7d906f999b82510ad0eab791bd092947107b

Present Behaviour

1. I followed my guide to setup a machine for Kiln.
2. I started the Geth service, the Lighthouse beacon node service and the Lighthouse validator client.
3. I watched the logs and everything seemed fine.
4. I restarted my Lighthouse beacon node service around Mar 10 21:40:04 UTC, before the beacon chain started on Kiln.
5. I noticed these logs: https://gist.github.com/remyroy/641f0ceabb05d9f977174c6550a1fb3f#file-lhbn-log-L1950

Expected Behaviour

Under normal circumstances, I expect the Lighthouse beacon node process to behave normally after a restart.

Steps to resolve

Restarting the validator client service solved this issue for some weird reason. I restarted my validator client around Mar 10 22:11:27 UTC and you can see in the logs that the WARN messages disappeared. Full validator client logs can be found on https://gist.github.com/remyroy/4334e9b0722155ae94917c2fc2aba744 .

Now it might be harder to reproduce as it seems you need a network that has not reached beacon chain genesis yet.