[IoT Core] Duplicate messages from topic forwarding rule

Hi,

I have created a topic forwarding rule in AWS IoT Core using this rule.

SELECT * from 'data/device01' WHERE temperature > 35

This rule forwards messages to the topic 'data/alarms'. I used QoS 0.

I observed duplicate messages like this from the subscription of 'data/alarms'

data/alarms
August 05, 2020, 14:36:01 (UTC+0900)
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{
  "device": "device02",
  "temperature": 35.02,
  "brightness": 12,
  "humidity": 87,
  "time": "2020.08.05 07:36:01"
}
data/alarms
August 05, 2020, 14:36:01 (UTC+0900)
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{
  "device": "device02",
  "temperature": 35.02,
  "brightness": 12,
  "humidity": 87,
  "time": "2020.08.05 07:36:01"
}

Interesting part is where sometimes there are duplicates and sometimes not.

Question: Is this expected behavior of IoT Core?

Thanks,