That's how it should work by default. Was it working before or it didn't work at all?
What type of content are you searching? (posts, pages, custom post types etc..?)
Can you provide temporary ftp and admin access to check on this issue? I have no other reports of WPML issues, so I don't know what could it be.
There is one known bug with the current version which affects a small percent of installations, but I don't know if it could cause this. To make sure that bug is not present, please open up the Fulltext search options and save the settings without changing anything. Please let me know if it affects the problem in any ways.Best,
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