The nginx reverse proxy configuration sets a dangerous Cache-Control header that likely isn't intended for most users.
add_header Cache-Control "public,max-age=31536000";
For non-crawler users, this directs their browser to cache the response for a year.
In my case, the webpages in my app are now refusing to update in client browsers because of this long cache policy. I'm trying to alleviate the issue by modifying the response etag, but in the end, it's up to the browser to decide to revalidate the cache even though the cache expiration is a year.