get_users( $args ) crashes database

I’m trying to use get_users( $args ) but one particular section causes the database on the site to crash; some sort of endless loop I think.

If I uncomment the lines of the first array here, then the problem arises. I really can’t see why since the array is very similar to subsequent arrays which do work.

Can anyone help here?

Many thanks!

$subscribed = array (
	'relation' => 'OR',
	// if the IM is ANY country we can show the casting
	//array(
	//	'key'     => 'im',
	//	'value'   => 'Email notifications - global',
	//	'compare' => 'LIKE'
	//),
	// or if it's a specific country
	array(
		'relation' => 'AND',
		array(
			'key'     => 'country',
			'value'   => $cCountry,
			'compare' => '='
		),
		array(
			'key'     => 'im',
			'value'   => 'Email notifications - my country only',
			'compare' => 'LIKE'
		)
	),
	// or if im hasn't been set (defaults to one country)
	array(
		'relation' => 'AND',
		array(
			'key'     => 'country',
			'value'   => $cCountry,
			'compare' => '='
		),
		array(
			'key'     => 'im',
			'compare' => 'NOT EXISTS'
		)
	)
);