I also get the same error:
Fatal error: PLL_Model::_languages_list(): The script tried to execute a method or access a property of an incomplete object. Please ensure that the class definition “PLL_Language” of the object you are trying to operate on was loaded _before_ unserialize() gets called or provide a __autoload() function to load the class definition in /home/content/p3nexnas05_data02/06/2113106/html/wp-content/plugins/polylang/include/model.php on line 192
The error is also intermittent. I have noticed that the error appears after I post something: be it a normal post or making a new page. It tends to disappear after some time (sometimes longer, sometimes shorter)
