24-105 Z - does it tend to overexpose?

Somehow I can't shake the impression that the 24–105 Z, when used with any of my EOS camera bodies, tends to slightly overexpose.
Have any of you noticed the same thing with your copy?

For example, when I'm shooting reportage in consistent daylight conditions: Av mode, wide open aperture, Auto ISO, I only find the exposure to look neutral, when I dial in between -1/4 and -1/3 EV exposure compensation.

I can't observe this behavior with any of my other Canon lenses, they used to be natural...