Strange chrome/vaadin upload/spring-boot bug

Hi, I posted this question https://stackoverflow.com/questions/52229696/strange-bug-in-chrome-69-0-3497-81-spring-boot-security-vaadin-when-uploadin to stackoverflow but I feel the place here might be more appropriate.

In short, using the Upload component and spring-security my application hangs after I have clicked on 5 different upload components (it hangs upon clicking on the 6th). This happens only with Chrome 69.0.3497.81 using spring-boot-security.

An example app can be found in https://github.com/npetalid/chromebug.git

Any help or pointer towards looking in the right direction would help.

Regards,

First thing that pops into my mind is that for some reason Spring Security creates new http session for each authorized upload, and you will run out maximum number of parallel supported http sessions with Chrome browser. See info here https://www.baeldung.com/spring-security-session how to change http session creation settings and here about http connection limits https://stackoverflow.com/questions/985431/max-parallel-http-connections-in-a-browser. If the reason is this, it is not a bug, but a feature.