Imperfect deleting #339

I got a notification, read the comment and then deleted the post.
In my notifications, the comment was still shown.
After clicking on the notification, the side crashed (Screen 1) and after that I saw an Error 404 (Screen 2).
I loaded the main-page and after that, nothing happens when I click on the notification.
Have I been too fast, is it a browserfault or a bug in the HC-System?
Why does the comment still appear in the notifications after the post was deleted?

Desktop-PC with Siduction and Firefox Quantum 60.2.2esr (64 Bit)

Screen 1: https://cdn.discordapp.com/attachments/497575240986263583/505074441424994315/Bildschirmfoto_vom_2018-10-25_19-24-33.png

Screen 2: https://cdn.discordapp.com/attachments/497575240986263583/505074476111757312/Bildschirmfoto_vom_2018-10-25_19-34-42.png

Greetings
Andreas