Mysterious intermittent 502 errors

[dqnykamp]

Intermittent 502 error are occurring on beta.doenet.org. Let's use this issue to track when they are happening to try to find the pattern and determine the cause.

[dqnykamp]

Got a 502 while editing a document. In the Javascript console, it says:
/api/updateContent/saveDoenetML:1 Failed to load resource: the server responded with a status of 502 (Bad Gateway)