No, it's not normal but already reported.
I think this was already reported in German, but after he sent me Private Message, I quoted him and I got this error..
The server encountered an unresolvable problem, please try again later.
And it still shows in Quotes (1), in lower right of screen, and clicking "Quotes (1)" bubble, it gives that error too.
Going back to that PC/private message again, clicking the title .. gives errors...
Fatal error: An error occured. Sorry.
Send this ID to the administrator of this website to report this issue.
Fatal error: Call to a member function getUserProfile() on a non-object in /var/www/woltlab/beta/wcf/templates/compiled/0_wcf_2_conversationMessagePreview.php on line 19
Please do not mix several errors into one thread.