On Wednesday, 27 Sep 2017 at 11:53, James Harkins wrote:
> Hi,
>
> There seems to be a mistake in the org-mode Ubuntu 16.02 packages.
>
> For beamer, if I C-c C-x p to add a property, one of the predefined options is:
>
>      :BEAMER_act(Act): 1

I think (could be wrong on this) that org includes any properties you
already have as pre-defined options available to you.  Maybe you have
this property already in your file?

-- 
: Eric S Fraga via Emacs 26.0.50, Org release_9.1-64-g657302