Deploying Lambda Layer using SAM CLI renaming file and preventing lambda functions from knowing where to look for packages

Question

I am working on an application, and we are utilizing SAM CLI to manage the deployment of our lambda functions. I am trying to refactor some of the functions to use a lambda layer so that shared packages are all managed in one place. There is a weird bug where deploying the layer through the CLI is renaming the file that is zipped and deployed to the layer from nodejs to <functionName-uuid>. The lambda functions are looking for the nodejs file for the packages, and cannot find it, so they error out.

In another environment, where the lambda layer is deployed through a Github action, this renaming does not happen, and the layer works as expected. As far as I can tell, the action is not deploying the SAM stack in a different way than the CLI commands. Why would this happen, and any advice on a fix?

simplified stack:

backend
  functions-sam
    functions
      myFunctionName
        app.js
    sumBySourceLayer
      nodejs
        package.json
        package-lock.json
        node_modules/
    template.yaml
src/
package.json

package.json script to deploy SAM stack:

"scripts": {
  "lambda:build": "sam build -t backend/functions-sam/template.yaml",
  "prelambda:deploy": "npm run lambda:build",
  "lambda:deploy": "source .env && sam deploy -t backend/functions-sam/template.yaml --stack-name SAM-$REACT_APP_ENVIRON --parameter-overrides environ=$REACT_APP_ENVIRON --profile $DEV_PROFILE",
},

simplified template.yaml:

Resources:
  SumBySourceLayer:
    Type: AWS::Serverless::LayerVersion
    Properties:
      LayerName: sumBySourceLayer
      Description: Layer for dependencies used by all functions
      ContentUri: sumBySourceLayer/nodejs
      CompatibleRuntimes:
        - nodejs14.x
        - nodejs16.x
    Metadata:
      BuildMethod: nodejs14.x

  MyFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: myFunctionName
      CodeUri: functions/myFunctionName/
      Handler: app.lambdaHandler
      Layers:
        - !Ref SumBySourceLayer

and the github action that is run manually when deploying to a staging environment:

name: 'Lambdas-deploy-staging'
on:
  workflow_dispatch:
jobs:
  build-deploy:
    environment:
      name: staging
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v2
        with:
          node-version-file: '.nvmrc'
      - uses: aws-actions/setup-sam@v2
      - uses: aws-actions/configure-aws-credentials@v1
        with:
          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
          aws-region: ${{ secrets.AWS_REGION }}
      - name: sam validate
        run: sam validate
        working-directory: './backend/functions-sam'
      - name: sam build
        run: sam build --use-container --parallel --no-cached
        working-directory: './backend/functions-sam'
      - name: sam deploy
        run: sam deploy --no-confirm-changeset --no-fail-on-empty-changeset --stack-name MissionPortal-SAM --capabilities CAPABILITY_IAM --region ${{ secrets.AWS_REGION }}
        working-directory: './backend/functions-sam'

When I download the layer deployed through the CLI:

When I download the layer deployed by the GH action:

Any help is appreciated.

I honestly don't really know what to try moving forward. I would expect the SAM CLI and the Github action to build and deploy the same stack.