Build Targeting Not Working

Fly config:

app = "k1insights"

kill_signal = "SIGINT"
kill_timeout = 5
processes = []

[build]
  build-target = "deploy"

[env]
  K1_DATA_DB = "/data/k1.db"
  K1_KART_LOOKBACK = 14
  K1_LOCATION_LOOKBACK = 7
  K1_POOL_SIZE = 100
  K1_TASK_LIMIT = 20
  K1_USER_LOOKBACK = 30

[mounts]
  source = "k1data"
  destination = "/data"

[[services]]
  http_checks = []
  internal_port = 5000
  processes = ["app"]
  protocol = "tcp"
  script_checks = []

  [services.concurrency]
    hard_limit = 25
    soft_limit = 20
    type = "connections"

  [[services.ports]]
    force_https = true
    handlers = ["http"]
    port = 80

  [[services.ports]]
    handlers = ["tls", "http"]
    port = 443

  [[services.tcp_checks]]
    grace_period = "1s"
    interval = "15s"
    restart_limit = 0
    timeout = "2s"

[experimental]
  allowed_public_ports = []
  auto_rollback = true

Dockerfile:

# syntax=docker/dockerfile:1

FROM python:3.8-slim-bullseye AS base

RUN apt-get update && apt-get -y upgrade && apt-get -y install git

FROM base AS compile

WORKDIR /app

RUN pip install -U build

COPY .git/ ./.git/
COPY LICENSE.md pyproject.toml supervisord.conf ./
COPY src/ ./src/

RUN python -m build -w

FROM base AS deploy

EXPOSE 5000

RUN useradd -m -G tty fakeuser && mkdir /data && chown fakeuser:fakeuser /data
VOLUME ["/data"]

WORKDIR /home/fakeuser
USER fakeuser

ENV PATH="/home/fakeuser/.local/bin:$PATH"
RUN pip install gunicorn supervisor

COPY --from=compile /app/dist/*.whl /app/supervisord.conf ./
RUN pip install *.whl

ENTRYPOINT (k1-create-db ${K1_DATA_DB} || true) && k1-start-all

flyctl deploy logs:

[...]
[Warning] One or more build-args [build-target] were not consumed

What am I doing wrong?

Anyone have any ideas about this?