This is the first mention of such a need, and really should not be a theme option.
I’m not sure what that plugin is supposed to do, or how it works or doesn’t.
Perhaps you could try the plugin with another theme such as one of the default WordPress Twenty-something themes. If it works with those, then there seems to be some incompatibility. If not, then perhaps the plugins is out of date, or you have not set it up properly.
Multiple authors does not seem like an easy thing to fix, however. Not even sure how a programmer would approach the solution.