NoMethodError using Avro codec with Kafka plugin


I'm using the Kafka input plugin version 2.0.8 to pull Avro-encoded messages from Kafka 0.8. I have the Avro codec version 2.0.4 installed, but when I push a message into Kafka, Logstash gives the following error:

{:exception=>#<NoMethodError: undefined method 'decode' for #<Array:0x3776056c>>...

The backtrace indicates this is happening right on the @codec.decode line in kafka.rb. Can someone shed some light on why this exception is being thrown?