ERROR chirpstack::uplink: Deduplication error error=No channel found for frequency: 923000000, dr: 4

Hello,

We are facing an issue in ChirpStack v4 where one AS923-1 gateway with the following log error:

no channels found for this frequency: 923000000

Setup

• ChirpStack v4

• Two gateways in the same property

• Both gateways have:

  Same AS923-1 region
  
  Same packet-forwarder config
  
  Same ChirpStack configuration
  

• Gateway type: Semtech UDP packet-forwarder

Gateway configuration (affected gateway)

• board_freq_band: AS923_1

• Uplink channels: 922.0 – 923.4 MHz

ChirpStack configuration

 [network]
 enabled_regions = [
   "as923",
   "as923_2",
   "as923_3",
   "as923_4"
 ]

Observation

• One gateway works correctly and processes uplinks as expected

• The other gateway (same configuration) logs:

  no channels found for this frequency
  

and uplinks are dropped

• Gateway stats and metrics are received normally for both gateways

• Issue is isolated to one gateway only

Questions

1. How does ChirpStack decide which AS923 region to apply per gateway when multiple AS923 variants are enabled?

2. Is it mandatory to explicitly bind each gateway to a single region (e.g. as923) to avoid this behavior?

3. Could an incorrect or missing region association cause only one gateway to be evaluated against the wrong AS923 variant, even if configs are identical?

Any guidance on the correct setup for multi-AS923 environments would be appreciated.

Thanks!