Is this a bug? G12 External flash power keeps resetting to zero

[spheredome]

I have this problem with external 270EX mounted on G12, no sure if this is a common or isolated unit. The flash power setting gets resetted to zero whenever the photo review button pressed.
This poses a problem when my adjustment gets reset to zero resulting in unexpected low flash with diffuser.

 

[spheredome]

CSC has confirmed the symptom and the list of affected flash include 580EX-II and 270EX. I have yet receive any remediation or if it is a new intended setting of the Canon G12 design.

Thus do test the following steps if you intend to buy a TTL flash for the G12.

1) Set the Flash EV power to any value with the TTL hotshoe flash inserted and power on.
2) Press the photo review button
3) Check the flash EV power again. The previous value must stay and not return to zero.

Onboard flash are no affected.