Hi,
I know this sounds like a drush issue, but bear with me.
I've just rm'd my whole Drupal 8 directory, git clone'd Drupal and re-installed it in Turkish. I then git clone'd my own project, and proceeded to enable it via drush (which has also been git clone'd 1 hour before these) and I got the warnings
rray_keys() expects parameter 1 to be array, null given [warning]
LocaleLookup.php:77
implode(): Invalid arguments passed LocaleLookup.php:77 Regards,
K.