Deploy Docker Image from Turbo Repo To DO Apps

I have a local server nodejs repository that I am pushing to Container Registry which in turn triggers a build on DO Apps.

My Dockerfile is not in the root though but under /apps/server/Dockerfile since I am using Turborepo. To point this out to DO, I added this file under the root of the repository: /.do/app.yaml

It contains this:

name: <NAME OF MY IMAGE>
services:
  - name: <NAME OF MY APP>
    type: docker
    repository: registry.digitalocean.com/<REGISTRY NAME>/<IMAGE NAME>:latest
    dockerfile_path: apps/server/Dockerfile

I can see that the deployment is kicked of when I push to the container repository but it fails immediately:

[server] [2023-05-31 18:34:10] starting container: starting sub-container [yarn workspace @my-server start:prod]: creating process: failed to load /usr/bin/yarn: exec format error

What is going on here? It seems like it is recognizing my Dockerfile under apps/server since it has the right start command: yarn workspace @my-server start:prod But why is it trying to load yarn from usr/bin/yarn?

Thanks for any help