Multiple account deployments with --aws-profile not working as expected

Serverless Framework
1

Hi.
I’m having an issue with multiple account deployments with Serverless.

I have two accounts configured as local profiles: test and production.
I’m using these profiles for a lot of things and they’ve worked fine for a long time. But I’m new with Serverless, so maybe I don’t quite understand what’s going on. I have the following config (truncated):

org: example
app: example
service: example
frameworkVersion: '3'

provider:
  name: aws
  runtime: nodejs14.x
  region: eu-west-1
  vpc:
    subnetIds: ${self:custom.subnets.${self:custom.stage}, self:custom.subnets.other}
    securityGroupIds:
      - { Ref: ExampleLambdaSecurityGroup }

  environment:
    NODE_OPTIONS: "--require ./.pnp.cjs"
    SEQUELIZE_HOST: ${ssm:/postgres-${opt:stage}/DbHost}
    SEQUELIZE_PASSWORD: ${ssm:/postgres-${opt:stage}/DbPassword}

Originally, I tried deploying this to my test profile and so far it worked fine. Now I was ready to deploy to my production profile, and I’m having issues with the Parameter Store values. It’s almost as if Serverless is looking at the wrong account/profile.

This is the output:

$ serverless deploy --stage production --aws-profile production --verbose                                                                                                                [8:59:41]
Environment: darwin, node 19.5.0, framework 3.26.0, plugin 6.2.2, SDK 4.3.2
Credentials: Serverless Dashboard, "123456789123-sls_dashboard" provider (https://app.serverless.com/example/apps/example/example/production/eu-west-1/providers)
Docs:        docs.serverless.com
Support:     forum.serverless.com
Bugs:        github.com/serverless/serverless/issues

Error:
Cannot resolve serverless.yml: Variables resolution errored with:
  - Cannot resolve variable at "provider.environment.SEQUELIZE_HOST": Value not found at "ssm" source,
  - Cannot resolve variable at "provider.environment.SEQUELIZE_PASSWORD": Value not found at "ssm" source

I know the variables exist - and even hardcoding them just to reference them directly yields the same error. I tried adding --verbose to the command in hopes that I could get some more information, but it doesn’t provide more output.

Might someone know what I’m doing wrong?