Think it might be a slight chink in the .htaccess file/s of the server. Might be incorrect yet never an issue to double-check, just playing security devil's advocate. If the .htaccess files let someone muck around with the PHP install, you might see errors like this.
*clears throat*
Of course, that's a big flashing neon sign for a signature too. "Oh look, here I am in your server crying havoc." In fair disclosure, if it were me, there'd be no traces left until I took over full root access of everything on the network the server is on. Even then, I'd play being a Casper, a "friendly ghost" that goes undetected. All the sysop might figure is the distribution developers were doing updates, upgrades. And yes, log files would only see that. No a-times would reveal my intrusion. I'd be a wisp, glimmering there and not.
*coughs*
Not me though. Why not? 1. I'm too damn honest. 2. I'm ethical. 3. That's trouble I do not need or want. 4. It goes against "path of the least resistance".
If I wanted a vaping forum site and network, I could "roll my own". I may be capable of doing it a lot cheaper as well, possibly more securely. Yes, can code html/Perl/Python/css/javascript/c/asm/awk/xml. Again though for me, "too much trouble".
Are there things here I might change? Irrelevant. Not my circus or show. I come, take a seat and enjoy as a humble free user of what is offered freely. Yes, I know my demographics are the product, don't mind up to a point. What point I mind, I use stuff here locally on my system to avoid. Got no call or right to "break in", or even suggest changes.
Also, those what know never say. Me, I'm just a goof what knows a little o' this, little o' that. Were I hm, motivated enough to be ambitious, I might be dangerous. As it is I'm "mostly harmless".
"Don't Panic!"