An SO user reported the same [0], and it seems others are effected [1] [2]. Heroku has not communicated an outage.
Anybody know what's going on?
[0]: https://stackoverflow.com/questions/68764077/heroku-h10-error-but-web-dynos-are-not-crashing
[1]: https://twitter.com/jaredbrown/status/1426164985550475264
[2]: https://twitter.com/Gemfury/status/1426154622645768192