We run 2 different apps on Heroku. Both have an API written with PHP and Symfony and run through an Apache. One of the frontend clients is written with Vue the other with Angular.
In the API we serialize command and query objects from the POST body. Sometimes this process fails because fields that are needed are missing. We know this through Sentry error monitoring. There we can look into those requests and all of them are missing the body entirely.
We're never been able to reproduce this case.
The issue spans over different endpoints, different browsers, different devices (mobile and desktop) without any common denominator other then the missing request body.
Are there known issues in the network layout, Apache or Heroku which would create that behaviour in an edge case like a very slow connection? Which would lead to a request being forwarded to the backend without the body? Is there any other thing without the application layout which could lead to this?