Using LR 2015.6.1 Release, Camera Raw 9.6
In the Book module I customized one of the 4 photo pages to add padding. Saved the customized page - everything appears to be fine. Now from a page in my book using that custom layout I click 'Add Page' and get this error:
Unexpected error performing command: bad argument #1 to 'getGeometryBounds' (userdata expected, got nil)
LR adds the page and everything seems fine. If I were to click 'Add Blank Page' then no error and I go to that page and select the custom page template and again no error.