qtranslate issue, fatal error on posts/news page in english

Hi guys,

I recently noticed that on my news page in english https://www.creativebox.bg/?page_id=259&lang=en this error has appeared: Catchable fatal error: Object of class WP_Post could not be converted to string in /home/creajtjg/public_html/wp-content/plugins/qtranslate/qtranslate_core.php on line 455.
I guess it’s a result of any wp/theme/plugin update, but I have no clue which one. For sure qtranslate is the trouble maker. I tried to roll back my updates, but with no result.

Anybody any idea?
Thanks in advance.