VSCode build task with dependsOn does "nothing" when gulp is installed. No output. How can I find the error?

I’m having problems with my VSCode installation, and I need some help to detect the cause of the error(s).

In one of my projects, I cannot (for some reason) execute any task that have "dependency tasks" defined. This is my .vscode/tasks.json file (created just to illustrate the problem):

{
    "version": "2.0.0",
    "tasks": [
        {
            "label": "subtask1",
            "type": "shell",
            "command": "echo This is a subtask"
        },
        {
            "label": "all",
            "dependsOn": [
                "subtask1"
            ]
        }
    ]
}

The task subtask1 runs fine. The output is "This is a subtask".

However, the task all does not run. When I select it from the list of tasks to run, nothing happens. The terminal output remains unchanged (whatever output was already there, remains).

Whatever I name the tasks, doesn’t matter. It seems that any task will not execute if it has a "dependsOrder" property defined.

This problem only persists when gulp is installed in the project dir (using npm i gulp).

My question is :

• How can I find the cause of this error and how can I fix it?

I’ve tried deleting the entire dir in %APPDATA%/Code, so the cache seems to be cleared. Then, I restarted VSCode. But the problem persists.