What's causing these colour shifts?

Took the E-PL1 for a walk to test my new VF2 and noticed I was getting inconsistent colour rendering between some similar subsequent shots.

The series below were taken in order and not much changes between the first and second shot in each case, but in each pair the first one looks almost overly vivid, while the second one looks more natural to muted.
OOC jpegs resized to 1024.

The exif is intact. Settings were as follows:
m14-42 lens
Aperture priority
WB set to cloudy
ienhance set to low
Gradation auto
esp metering

The first 2 I changed the aperture
The second 2 the focal length is different
The last 2 the only difference is the shutter speed

Apart from slightly different compostion, there's not much difference in the frames yet the camera has given me 2 different versions of rendering each time...

 

Yes I can only think of ienhance being the culprit too.

It's a pity because I thought it was the best picture mode (when set to low effect in the picture mode menu).
I've been getting great ooc jpegs since switching to low i-enhance, but I can see now that the final output is open to it's interpretation and how it feels a certain scene should look!

Strange though that I haven't noticed these discrepencies before using ienhance.