Updating process in LR4 unexpectedly zeroes out exposure brush value.

Possible. I will check it out and see.

I can see what's the problem.

You're trying to sync some global adjustments from a PV2012 image to a PV2010 one. In the process, you're expecting local adjustments on the target photo to update themselves to the new process too, even though you're not syncing them.

But, I am not sure Sync or Copy/Paste are supposed to update any adjustment to a newer process. Technically, they're doing what they are supposed to do: copying adjustment values from one image to another.

I think I'll report it as bug and see what's the official response.

> you're expecting local adjustments on the target photo to update themselves to the new process too

Actually I am not looking for the adjustments to be "right" aftet sync applies PV2012, just "still there".

The typical scenario is a photo which has been worked on some time ago, with lots of dodging and burning etc. Client wants a new set of prints so we look at the session photos and decide to sync the whole lot to the new 2012 engine. We expect to have to go in and tweak things, but setting adjustment brush values to zero and making all the dodging and burning disappear is a little strange (or buggy).

Thanks for the interest in this. Let's see whether you can get an official response.

I think a reasonable workaround for the time being is updating the target images to PV2012 (push that "!" button) just before syncing or pasting.