What does the exception "javax.servlet.jsp.JspException: Broken pipe" signify?

I am sure the underlying package uses pipes internally to transfer the result from a to b. Now B (the ServletOutputStream) closes, and the other end of the pipe notifies this by throwing this exception.

I am thinking that it has to do with end users closing their web browser before the page reloads/executes the next step

You are entirely correct. This exception will be thrown when the client aborts the current request by navigating away, closing the tab/window, refreshing the request, etc while the request is still running. In other words, the client abruptly closed the connection and the server side can't write/flush any byte to it anymore. It has normally an IOException as the root cause, usually in flavor of a servletcontainer specific subclass like ClientAbortException in case of Tomcat and clones. If you investigate the entire stacktrace in the server logs, you'll find it somewhere at the bottom.