Logstash reads my entry 2 times (or more)

Elastic Stack Logstash
1

When I use elasticsearch input, sometimes logstash refers several times my result in succession.
I don't understand why.
Sometimes it works, sometimes not and nevertheless neither my configuration nor my data changed.

2

Providing your config as well as what versions of things you are using would be helpful.

3

I use logstash 1.5.4 and logstash-filter-elasticsearch 0.1.6 and my conf files look like :
input {
elasticsearch {
hosts => ["my host"]
index => "my index"
query => 'my query 1'
type => "my type 1"
scan => false
}
}
filter {
elasticsearch {
hosts => ["my host/my index/my type 2"]
query => "my query 2"
fields => ["my fields:my fields"]
}
...