Cisco Firewall :: ASA 5520 - Threat Detection Provoke Frequent Disconnections On Allowed Traffic?

Can threat detection provoke frequent disconnections on allowed traffic?We are using  asa 5520 with 8.3.1 IOS For instance in ASDM we see SYN attack messages .The source ip address correspond to external an external host (in the outside interface) wich is allowed to connect to  internal servers(in the internal interfaces).
 
Our threat conf is as follow:
 
threat-detection rate dos-drop rate-interval 600 average-rate 100 burst-rate 400
threat-detection rate dos-drop rate-interval 3600 average-rate 80 burst-rate 320
threat-detection rate bad-packet-drop rate-interval 600 average-rate 100 burst-rate 400
threat-detection rate bad-packet-drop rate-interval 3600 average-rate 80 burst-rate 320
threat-detection rate acl-drop rate-interval 600 average-rate 400 burst-rate 800
threat-detection rate acl-drop rate-interval 3600 average-rate 320 burst-rate 640

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