"false" string added to src attribute

Version: 3.6.2

Today I installed the plugin, configured it.
I wanted to try the lazy loading option.
Unfortunately the pictures were not loading.

The string false is appended to the beginning of the src tag of each image

src = "https: //domain.com/falsewp-content/uploads/..."

I temporarily modified the placeholder.cls.php file
function: replace ($ html, $ src, $ size)
line: 177

"$html = str_replace ('<img', '<img data-lazyloaded =" 1 "'. $additional_attr. 'src ="'. str_replace ('false', '', $ this_placeholder). '"', $ html);

Now the pictures are loading correctly.