Docker context (directory) not set consistently?

[sherland]

I'm new to Nx, so not sure if / how this is supposed to work, but here goes:
I want to create a nginx base-container that will be used by some of the other containers in the monorepo.

I create a new folder "Applications\nginx", (where all the other applications are located) and added package.json and project.json. (Content at the end)

Then I add a nginx.conf with appropriate content, and created the Dockerfile with this content:

FROM docker.io/nginx:stable-alpine
COPY /nginx.conf /etc/nginx/nginx.conf

By coincidence, I was in the Applications\nginx directory. when I ran nx run nginx-base-image:container

This was working as it should. However then I navigated to the root of the project and ran nx run nginx-base-image:container again. Now the container could not be built. I had to change Dockerfile to this:

FROM docker.io/nginx:stable-alpine
COPY Applications/nginx/nginx.conf /etc/nginx/nginx.conf

Does this mean that the docker build context is just set by random to whatever directory i'm starting the build from?

BTW: I'm using Rancher Desktop, not Docker Desktop, and I get this to the console when building:

>  Buildx version 
[command]"C:\Program Files\Rancher Desktop\resources\resources\win32\bin\docker.exe" buildx version
github.com/docker/buildx v0.12.0 542e5d810e4a1a155684f5f3c5bd7e797632a12f
Unsupported CI Provider... Using Local Environment as fallback
[command]"C:\Program Files\Git\cmd\git.exe" log -1 --pretty=format:%ae
plamen.totev@icb.bg[command]"C:\Program Files\Git\cmd\git.exe" symbolic-ref HEAD
refs/heads/master
[command]"C:\Program Files\Git\cmd\git.exe" rev-parse HEAD
01ea355452c4bce35ce9916d50ce46d08d7a4b54

--- Other files
package.json:

{
  "name": "nginx-base-image",
  "version": "1.0.0",
  "scripts": {},
  "author": "Team Triton",
  "dependencies": {},
  "devDependencies": {},
  "browser": {}
}

project.json:

{
  "name": "nginx-base-image",
  "$schema": "../../node_modules/nx/schemas/project-schema.json",
  "prefix": "",
  "targets": {
    "container": {
      "executor": "@nx-tools/nx-container:build",
      "dependsOn": [],
      "options": {
        "engine": "docker",
        "metadata": {
          "images": ["nginx-base-image"],
          "load": true,
          "tags": [
            "type=schedule",
            "type=ref,event=branch",
            "type=ref,event=tag",
            "type=ref,event=pr",
            "type=sha,prefix=sha-"
          ]
        }
      }
    }
  }
}