Flex box does not work with ie 11 > 9, you need to adjust the height for ie 11

ie.js

function ieTag(){
	var	ie = {
		 	eleven: 'rv:11', 
			ten: 'MSIE 10',
			nine: 'MSIE 9'			
		};
	
		var appVersion = window.navigator.appVersion;
		
		for( key in ie ) 
		{
				
			if ( appVersion.indexOf(ie[key]) !== -1 )
			{
				$('html').attr('id', "ie"+key); 	
			}	
		}	
	
}

style.css

#ieeleven #staff .person, #ieten #staff .person, #ienine #staff .person{ 
	height: 200px; 
}