I have tried to sniff the packets from the Fortianalyzer and able to see the packet being received for the standby(slave) unit on Fortianalyzer but not for the Active Unit. 
 
 SIN-FW-02 (global) $ diag log test                    
 
 generating an allowed traffic message with level - warning
 generating a system event message with level - warning
 generating a HA event message with level - warning
 generating a infected virus message with level – warning
 generating a blocked virus message with level - warning
 generating an attack detection message with level - warning
 generating a blacklist email message with level - warning
 generating a URL block message with level - warning
 generating an IM message with level - warning
 generating a VOIP message with level - warning
 
 FortiAnalyzer-800B $ diagnose sniffer packet any ' host 57.33.94.70'  4 
 interfaces=[any]
 filters=[host 57.33.94.70]
 nr=576,fr=1680,b_nr=288,pg=4096
 6.221373 57.33.94.70.7130 -> 10.1.6.218.514: udp 434
 6.221391 57.33.94.70.7130 -> 10.1.6.218.514: udp 190
 6.221395 57.33.94.70.7130 -> 10.1.6.218.514: udp 164
 6.221398 57.33.94.70.7130 -> 10.1.6.218.514: udp 290
 6.221401 57.33.94.70.7130 -> 10.1.6.218.514: udp 290
 6.221609 57.33.94.70.7130 -> 10.1.6.218.514: udp 400
 6.221610 57.33.94.70.7130 -> 10.1.6.218.514: udp 277
 6.221613 57.33.94.70.7130 -> 10.1.6.218.514: udp 200
 6.221613 57.33.94.70.7130 -> 10.1.6.218.514: udp 232
 6.221984 57.33.94.70.7130 -> 10.1.6.218.514: udp 252
					
				
			
			
				
	Regards,
Subbu