Behaviour

Getting a warning annotation appearing on workflows that use docker/setup-buildx-action:

docker: invalid reference format. See 'docker run --help'.

Steps to reproduce this issue

1. uses: docker/setup-buildx-action@v1 in your workflow
2. look at the action run summary page after triggering your workflow

Expected behaviour

Should not warn about a command run from within the action

Actual behaviour

Puzzling warning about a command I didn't run

Configuration

name: CICD
on:
  pull_request:
  push:
   branches: [master]

jobs:
  build-test-push:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v2
      - uses: docker/setup-qemu-action@v1
      - uses: docker/setup-buildx-action@v1

Logs

setup-buildx-action.log

The warning annotation is coming from the end:

2021-06-29T10:52:22.9660083Z ##[group]BuildKit version
2021-06-29T10:52:23.0610726Z ##[warning]docker: invalid reference format.
See 'docker run --help'.
2021-06-29T10:52:23.0631583Z