#1. ERROR chirpstack::uplink: Deduplication error error=join-request payload must be exactly 18 bytes

Hi Team,
I’m seeing an error in the logs.

ERROR chirpstack::uplink: Deduplication error error=join-request payload must be exactly 18 bytes

docker logs chirpstack-docker_chirpstack_1 output:

025-11-27T04:53:20.258225Z  INFO chirpstack::gateway::backend::mqtt: Message received from gateway region_id="eu868" topic=VDMS783_eu868/gateway/647fdafffe0159a3/event/up qos=AtMostOnce json=false
2025-11-27T04:53:20.333449Z  INFO chirpstack::gateway::backend::mqtt: Message received from gateway region_id="eu868" topic=VDMS783_eu868/gateway/647fdafffe0159a5/event/up qos=AtMostOnce json=false
2025-11-27T04:53:20.448292Z  INFO chirpstack::gateway::backend::mqtt: Message received from gateway region_id="eu868" topic=VDMS783_eu868/gateway/647fdafffe0159a3/event/up qos=AtMostOnce json=false
**2025-11-27T04:53:20.460139Z ERROR chirpstack::uplink: Deduplication error error=join-request payload must be exactly 18 bytes**
2025-11-27T04:53:20.531909Z  INFO chirpstack::gateway::backend::mqtt: Message received from gateway region_id="eu868" topic=VDMS783_eu868/gateway/647fdafffe0159b0/event/up qos=AtMostOnce json=false
2025-11-27T04:53:20.650178Z  INFO up{deduplication_id=5295d40b-2ee4-4ff0-a889-bde4f6f54e00}: chirpstack::uplink: Uplink received m_type=UnconfirmedDataUp
2025-11-27T04:53:20.656632Z  INFO up{deduplication_id=5295d40b-2ee4-4ff0-a889-bde4f6f54e00}:data_up{dev_eui="70b3d52c000265ec"}: chirpstack::storage::device_gateway: Gateway rx-info saved dev_eui=70b3d52c000265ec
2025-11-27T04:53:20.657204Z  INFO chirpstack::integration::http: Posting event event=up url=http://XX.XXX.XXX.XXX:9888/apiv4/decodelorawansensorevent
2025-11-27T04:53:20.657325Z  INFO chirpstack::integration::mqtt: Publishing event topic=application/00000000-0000-0000-0000-000000000002/device/70b3d52c000265ec/event/up

Could someone help me understand what might be causing this “payload must be exactly 18 bytes” error?

Thanks!