You may consider upgrading to the newest version of OJS 3, but this may help. It’s against 3.1.2 for OMP, but the codebases are shared and so this may help:
I applied the patch but it did not work
I have detected the following:
The authors can see the names of the authors, when they have the author profile.
Are you both an author and a reviewer on the same submission, though? In that case, yes, you’d be able to see the names of the other authors (since you’re also an author on it).