I connect to the topic, I have a similar problem, the menu after running over the same scanned (recognition) language pages from polylang itself wtycznki installation, activation and adding language than harm does not cause damage only to scan the menu, please help.
@ssdenis89, did you solve your issue? If yes, I’m curious to know what you did.
I have also an issue on WP Engine with Polylang : the menu bar disappears and the menu is displayed only in the main language.
I had a similar issue and it was due to a bad configuration in the WPE portal.
It happen when you force https for admin and login but not for the site.