Forums are still essentially unusable. Search is broken, nearly every time I try using it. Only way to use them is to check daily for what I'm looking for manually, but that's not practical;
A 500 error is generally not caused by the web server or hoster itself, it's almost always caused by coding errors in the software that runs the site, or in the configurations, like .htaccess/httpd.conf etc.
If the page initially loaded, it's not caused by the configuration files, but by the programming.
Also, the notion that "it's getting better and happens less often" is not a real thing in programming, the bug is clearly there and active, or rather, the bugs, since I just triggered them myself just now attempting to do a forum search. Zero success.
Note: I just retried forum search, and it suddenly worked.
Also, I tried emailing to the email contact listed in the 500 error message, and that returned as a bounced email.
This kind of randomness means badly broken code and logic.
What's odd is the total randomness of it, I had not tried to do a search for a while, maybe a month, then I did one just now, both resulted in 500 errors, then while typing this, I opened a new tab (the others had also been a new tab), and the advanced search, including the most recent option, suddenly worked. That latter one almost never works, though sometimes the general search does work.
These are all huge red flags, which I tried to alert the forum people about in private, but given not even the contact email listed is valid in the error page, it's apparently a lost cause, but I'll keep poking in hopes that the situation can be rectified before something much worse happens, probably again I would guess, though I don't know the history.
Sometimes odd behaviors like this are the result of misconfigured apache or other web server security rules, but those don't result in a server 500 error, they just result in the post vanishing. As far as I can tell, you can't post any real code or data in the posts with any hope of success.
I suggested this before, and I'll suggest it again, talk to linuxquestions.org, ask for a distro sub forum, and give up on this effort. Having a forum that doesn't work consistently might be almost worse than having no forum at all I think. It's hard to even start to guess what happened to these, my guess was, and continues to be, the ill-advised attempt to mix a wiki software package and the forum software packages, but that's just a guess.