Lead Developer
Hmm, I’m afraid you’ll have to contact the Polylang developers and let them know that it’s happening.
You can tell them the issue is probably caused by WordPress’ new title-tag feature, which they should definitely integrate into their next version: https://make.wordpress.org/core/2014/10/29/title-tags-in-4-1/
Sorry I can’t be more helpful! Let me know what they say.