I imported and published the new set of customizations I'd been working on from my development environment to UAT. When the testers went in to test the new customizations, they noticed that duplicates were being introduced in the system (yet again).
Sure enough, when I looked at the duplicate detection rules, they were unpublished (again). This time, I knew I'd published them previously and investigated more deeply. I discovered this is expected behavior. By design, whenever any entity metadata is changed all duplicate rules associated with that entity are unpublished.
so after changing the meta data or any changes in schema solution we need to publish the duplicate detection rule again.