[TYPO3-mvc] TYPO3 renders blank page *sometimes*

[Marcus Budzyn]

I set [SYS][sqlDebug] = 2 and set the IP mask to display all queries. 

This works fine, the queries are displayed above the real content.

But the page remains empty (no queries shown!) when TYPO3 tries to render that "empty page". 

No queries are displayed, the page remains empty.