DynamoDbIgnoreNulls is not working as expected

[dariellbowo]

This is a duplicate of #3499

I am using DynamoDB Enhanced Client to update partial attribute.

Reproduction Steps

@DynamoDbBean
public abstract class Parent {
    private Integer id;
    private Instant createdTimestamp;
    
    @DynamoDbPartitionKey
    @DynamoDbAttribute("id")
    public Integer getAccountId() {
        return id;
    }

    @DynamoDbAttribute("created_timestamp")
    @DynamoDbUpdateBehavior(UpdateBehavior.WRITE_IF_NOT_EXISTS)
    @DynamoDbAutoGeneratedTimestampAttribute
    public Instant getCreatedTimestamp() {
        return createdTimestamp;
    }
}
@DynamoDbBean
public class Child{
    private String attribute1;
    private String attribute2;

    @DynamoDbAttribute("attribute_1")
    @DynamoDbIgnoreNulls
    public String getAttribute1() {
        return attribute1;
    }

    @DynamoDbAttribute("attribute_2")
    @DynamoDbIgnoreNulls
    public String getAttribute2() {
        return attribute2;
    }
}

client = enhancedAsyncClient.table(tableName, TableSchema.fromBean(Child.class));

Child child = new Child(777, "someValue1", "someValue2");
client.updateItem(child);

Child updatedChild = new Child(777, "someValue3");
enhancedAsyncClient.table(tableName, TableSchema.fromBean(Child.class)).updateItem(child);
client.updateItem(updatedChild);
// After this statement attribute2 will be empty while attribute1 is updated to "someValue3"

Originally posted by @dariellbowo in #3499 (comment)