POST + 500 + Response returns no content

[Marc Boorshtein]

I'm running tomcat 8.0.41 on a CentOS7 Docker container.  Something very
strange is happening.  If I use a GET and return a 200 with JSON content
the data gets back to my browser.  But if I run a POST and return a 500
with the content being JSON written to response.getOutputStream()
(including a flush) I get no content getting back to my browser.  I can see
the content being written and on a flush response is setting isCommited to
true.  What am I missing?

Thanks