Intermittent outages on Stack Overflow near 3 AM UTC

Any attempts to visit Stack Overflow for a few minutes following 3 AM UTC results in the browser showing the 500 Internal Server Error page, not even the Oops! Something Bad Happened! page. Chat seems unaffected, as do other sites on the network, including Meta Stack Overflow. The outage subsides after a few minutes but seems to be recurring at around 3 AM UTC every day I checked.

Also, separately, this is around the time that the RemoveAbandonedClosed Roomba script runs. Might be a coincidence, but might be related, for example, if the script running somehow blocks the server from responding to other requests.