My PHP error logs are filled with a PHP Notice, occurring every few minutes:
Undefined index: tags in /path/qa-include/qa-app-format.php(1466) : eval()'d code on line 59
I checked my theme and plugins and the only use of a "tags" index was in my tagging tools plugin, which as far as I know should always be defined (it's in the $params variable passed to the event function). Nonetheless, I suppressed any possible notice with @ but the notices still come, so I think it must be somewhere in core Q2A code?
Because of the eval the notice isn't particularly helpful in finding where the problem might be. I've tried matching the times for the notices to things happening on the site but I haven't found anything conclusive.