Page translations are not found when searching for tags

Follow this steps to reproduce:

• Enable multilingual from the Wiki Administration and add French as a supported language
• Go to the Sandbox page and add a tag "robot"
• Switch to French language (from the URL)
• Search for "robot". You get not results.
• Look at the Language facet. It says there is a result for English.
• Check the English option. You get the result.

It looks like Solr doesn't find page translations when searching for tags.