The page https://nl.wikipedia.org/wiki/Speciaal:OngekoppeldePaginas?iwdata=only sometimes generates a time-out on the database connection. When this happens it looks like a MySQL error message is generated instead of an errormessage by MediaWiki.
The error message I get is:
A database query error has occurred. This may indicate a bug in the software. Function: Wikibase\Client\Specials\SpecialUnconnectedPages::getResult Error: 2013 Lost connection to MySQL server during query (10.64.48.16)
(This is the full text that is displayed on the page, no graphics or anything)