Oh, if I had a nickel for every time I've said "That's impossible".
Is it impossible that the site is running with error_reporting(0) and some unanticipated error condition occurred?
I did not check the code for myself as it is not my site, and I was trying to help someone without technical resources. I doubt they modified any code, but it's not "impossible".
In fact, something did go strange when I first registered to the site. My browser locked up and I rebooted. When I went back to the site, I could login and get to the forum, post, etc., but my profile email field was blank. I could apparently form email to other members, but they never received it until I entered the email address.
Let us just say that this trouble ticket would be marked "Unable to reproduce".