DigitalOcean App Platform does not parse ${db.DATABASE_URL} after bulk editor changes

I am using DigitalOcean App Platform to deploy a Django app. The initial deployment worked fine, but I’ve attempted to use the bulk editor on the component-level environment variables, and since then, the deployment fails when executing dj_database_url.config(default=config('DATABASE_URL').

For debugging, I added this line to settings.py:

print(f"[BUILD DEBUG] DATABASE_URL = {repr(os.environ.get('DATABASE_URL'))}")

This returns [BUILD DEBUG] DATABASE_URL = '${db.DATABASE_URL}' in the build logs.

I don’t understand why the environment variable is not resolving. My app spec looks like this:

services:
- environment_slug: python
  envs:
  - key: DATABASE_URL
    scope: RUN_AND_BUILD_TIME
    value: ${db.DATABASE_URL}

Could this be a bug, or am I doing something wrong? Yes, my database is named correctly:

databases:
- engine: PG
  name: db

The only thing that changed between my last deployment and this failed deployment, besides a few lines of code, is that I used the bulk editor to add new environment variables. Some of the existing environment variables were encrypted, but they look OK in the app spec.