Update-function-configuration fails

[conan]

aws lambda update-function-configuration --role arn:aws:iam::1<snip>4:role/cljs-lambda-default --runtime nodejs8.10 --memory-size 1024 --timeout 6 --handler index.referralbot_core_SLASH_refer --function-name referralbot-slash-command --vpc-config SubnetIds=[],SecurityGroupIds=[] --dead-letter-config TargetArn= --environment Variables={}
usage: aws [options] <command> <subcommand> [<subcommand> ...] [parameters]
To see help text, you can run:

  aws help
  aws <command> help
  aws <command> <subcommand> help

Unknown options: --dead-letter-config, --environment, Variables={}, TargetArn=

If I make a change to config (rather than code), lein cljs-lambda deploy fails with the above error. I have to delete the function and start again in order to make the change.

$ aws --version
aws-cli/1.11.13 Python/3.5.2 Linux/4.4.0-17134-Microsoft botocore/1.4.70

[moea]

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