If you install Searchanise in a store and clone this store's database to another store, the search results will be messed up. This is why we strongly recommend clean installations for new stores.
Searchanise identifies shops by unique API keys stored in the shops' database. When you clone a shop's database, you effectively create 2 Searchanise installations with the same API key, and the search results become mixed.
The proper way to resolve this issue is to uninstall Searchanise, delete database tables that store the API keys, and install Searchanise anew.
1. Uninstall Searchanise via Magento Connect Manager
2. Delete the searchanise_config and searchanise_queue database tables
3. Execute this SQL query:
DELETE FROM core_resource WHERE core_resource.`code` = ‘searchanise_setup’
4. Install Searchanise from Magento Connect Manager
5. In the other Searchanise installation, click Force re-indexation