get_the_excerpt filter runs twice with custom snippets

I’ve created a function to amend excerpts using the ‘get_the_excerpt’ filter. Its purpose is to add a ‘More…’ link at the end of the excerpt. When enabling the Relevanssi feature to use custom snippets for the excerpt, the filter is applied twice for each excerpt and so displays two sets of More… links.

http://wordpress.org/extend/plugins/relevanssi/