You didn’t mention which version you’re using (e.g. 3.3.0-13), but in case you’re not running a later version like 3.3., then it is best to upgrade, as OMP indexing for Google Scholar is supposed to have been fixed as of OMP 3.3 (see here: How to make Google Scholar harvest the OMP metadata - #21 by Nikola) Do you know if you are running OMP 3.3 or later?
-Roger
PKP Team