This is getting out of hand. Tth yet again gave me trouble, and brute force method let me narrow the source down to this bit:
Or alternately:
Point is, as of yesterday, that I noticed at least (seems to me, with me, if it isn't ao3, it's tth where problems crop up *sigh*), is_adult does not play well with username and password.
Now, to be sure, I've noticed that if I simply delete username & password, it works perfectly fine. And since tth, as far as I know, isn't like ao3, in that there aren't some fics that are only accessible to registered users, it's a feasible option.
But I still can't help but wonder just what changed that this problem suddenly cropped up. Any ideas on that front?