From JCLuaLibrabry.php:

		$content = JCSingleton::getContentFromLocalCache( $jct );
		if ( $content === null ) {
			$this->incrementExpensiveFunctionCount();
			$content = JCSingleton::getContent( $jct );

This makes the result depend on current server load, when was the last train deploy and other factors that influence cache pressure but aren't and shouldn't be obvious to end users. Page parse results should be predicable, so JC should just always up the counter.