You have set the path for config directory and it is not being set correctly.

Issue

You have modified and set the path for config directory in your settings.php like - 

$settings['config_sync_directory'] = 'your/config/sync/directory/path'
$settings['config_vcs_directory'] = 'your/config/vcs/directory/path'

for you Acquia Cloud site and it is not being picked up correctly, and instead the default path is being picked up like - path/to/docroot/sites/sitename/files/config_HASH

Resolution

You can try moving the above two lines for the config directory path after the default Acquia line in settings.php, which will be after the following section - 

   if (file_exists('/var/www/site-php')) {
        require('/var/www/site-php/mysite/mysite-settings.inc');
        }