QtCreator merging stderr and stdout without being told to

[Mookie]

QtCreator 3.0.1 (on an Unbuntu system) appears to be merging stdout and stderr in my Compile Output pane, likewise errors don't appear in the Issue pane.

Tools | Options | Build & Run | General | "Merge stderr and stdout" checkbox is unchecked.

Any ideas on how to fix this?
I checked to see if my project has some sort of override of global system settings, but couldn't find this one.

[Mookie]

Scratch this question.
I was a fool. It's just my Google Test output and not the compiler output that's sending to stdout.