Board Thread:Support Requests - Getting Technical/@comment-28712089-20170426193741/@comment-168424-20170512212952

So you're taking a module from one place and a template from another... Why did you think it would work? I think I told you earlier you can mix these things by taking one thing from one place and another from another. You still haven't said specifically where they came from. This makes it very hard to help you.

My first guess is that the Unsubst module comes from Wikipedia and is not compatible with Wikia lua. This is further re-enforced by me not finding "mw.isSubsting" anywhere on dev.wikia.com. So it likely cannot work and cannot be fixed.