I have Lambda Function which attached to DynamoDB change event. 
The Lambda is triggering twice when I change/modify an item in the Test-machines table in the DynamoDB.

I am modifying `IsMachineOn` value from `True` to `False`, It is trigger `Test-Machine-On-alert-status` Lambda function twice. 

I am not understanding why two-time lambda is a trigger.

I observed a small change in the `records` in the `event` parameter of Lambda.

**For first trigger**, 

Value of `NewImage["IsMachineOn"]["BOOL"]` is `False`

Value of `OldImage["IsMachineOn"]["BOOL"]` is `True`

**For Second trigger**, 

Value of `NewImage["IsMachineOn"]["BOOL"]` is `False`

Value of `OldImage["IsMachineOn"]["BOOL"]` is `False`

I have business logic on `NewImage["IsMachineOn"]["BOOL"]==False` so that my business logic is running twice.

There are two things:

1. Why Lambda is running twice?
2. What will be a workaround to fix this issue?