Exchange GRT level restores from datadomain as OST target

I was under the impression that Backup Exec 2012 could perform GRT level Exchange restores from a datadomain (used as a OST target) without having to rehydrate the entire edb. I actaully though I had tested this prevously in my 2012 environemnt that that the GRT restore did not have to rehydrate the edb, but when perform a GRT restore today the entire edb was rehydrated before restoring the missing emails.

This is with Echange 2010.