The Amplify app changed the platform without outside intervention

[JZechy]

Environment information

"amplifyfinbobbohemikaamplifyapp26797FB3": {
      "Type": "AWS::Amplify::App",
      "Properties": {
        "BasicAuthConfig": {
          "EnableBasicAuth": false
        },
        "BuildSpec": "version: 1\nfrontend:\n  phases:\n    preBuild:\n      on-failure: CONTINUE\n      commands:\n        - npm ci\n    build:\n      on-failure: CONTINUE\n      commands:\n        - API_URL=$API_URL OLD_APP_URL=$OLD_APP_URL CONFIG_NAME=$CONFIG_NAME CLOUDFRONT_URL=$CLOUDFRONT_URL ENVIROMENT=$ENVIROMENT npm run generate\n  artifacts:\n    baseDirectory: .output/public\n    files:\n      - \"**/*\"\n  cache:\n    paths:\n      - node_modules/**/*\n",
        "CustomRules": [
          {
            "Source": "/<*>",
            "Status": "404-200",
            "Target": "/index.html"
          },
          {
            "Source": "</^[^.]+$|\\.(?!(css|gif|ico|jpg|js|png|txt|svg|woff|ttf|map|json)$)([^.]+$)/>",
            "Status": "200",
            "Target": "/index.html"
          }
        ],
        "EnvironmentVariables": [
          {
            "Name": "CONFIG_NAME",
            "Value": "bsf"
          }
        ],
        "IAMServiceRole": {
          "Fn::GetAtt": [
            "amplifyfinbobbohemikaamplifyappRole33D84F09",
            "Arn"
          ]
        },
        "Name": "FinBOB-Bohemika",
        "OauthToken": {
          "Fn::Join": [
            "",
            [
              "{{resolve:secretsmanager:",
              {
                "Ref": "SsmParameterValuefinbobsecretgithuboauthC96584B6F00A464EAD1953AFF4B05118Parameter"
              },
              ":SecretString:::}}"
            ]
          ]
        },
        "Platform": "WEB",
        "Repository": "https://github.com/Bohemika-eu/bsf"
      },
      "Metadata": {
        "aws:cdk:path": "finbob-bohemika/running-environments/deployment-support/amplify/finbob-bohemika/amplify-app/Resource"
      }
    }

Describe the bug

We have AWS Amplify Applicationm described by Infrastrcture as Code through AWS CDK. We created the application with platform WEB, because we are using a static site generator. How the application was created and how it is still described in the CloudFormation stack can be seen in Environment Information.

This was perfectly fine until our application switched to the WEB_COMPUTE platform on its own today. Nothing has changed in the CDK code, the application is still described in CloudFormation as above. Other users do not have permission to change the application settings, and at the same time no one could - The option to switch platforms is simply not available in the interface.

This is critical behaviour for us. We can't simply switch our workflow to SSR to use WEB_COMPUTE. And this change is now blocking our deployments, because obviously a different output is expected. We need to transition our platform back.

I would like to add that such critical arbitrary changes are not happening for the first time in a new application backend. When updates to the functionality of the Production Branch settings has been applied, our production branch was automatically switched to the development branch. As a result, the end users got a completely bad environment that was in operation for several hours.

Reproduction steps

No steps to reproduce.