I hope, this is a unknown issue. Ich couldn’t find this here and it’s still in the sandbox.
It’s possible that the user can choose step “0” in the number rating poll GUI. When you’re doing that, it is possible (depends on browser and so on), that your device (PC) will lock up instantly (the cause is obviously, without seeing the code - it does not terminate?..). So you have to force shut-down and reboot. I think this option should be therefore forbidden. In the best case even the manual insert should be forbidden, too (note/warning, when you try to send post).