Warning: Illegal string offset 'default' in Drupal\gmap\GmapDefaults->

Hello i catch warning on php 5.6

Warning: Illegal string offset 'default' in Drupal\gmap\GmapDefaults->__construct() (linea 58 di /var/www/public/*****/sites/all/modules/gmap/lib/Drupal/gmap/GmapDefaults.php).

I tried on many website in my server web and get ever the error. I tried in a different hosting with the same PHP version and the error not showing.
I also tried with previously drupal version and more recent and it's the same.
I think this caused by php.ini configuration but I don't know where.

Can you help me?