Error Command "deduplicate" not found

On Ubuntu 20.04.3 LTS, I installed the git master version of jupyterlab according to the official guidance as follows:

$ pyenv shell datasci
$ python --version
Python 3.9.1
$ git clone jupyterlab.git 
$ cd jupyterlab.git 
$ pip install -e .
$ jlpm install
$ jlpm run build  # Build the dev mode assets (optional)
$ npm install yarn-deduplicate
$ jlpm run build:core  # Build the core mode assets (optional)
yarn run v1.22.17
$ cd jupyterlab/staging && jlpm && (jlpm deduplicate || jlpm) && jlpm run build
[1/5] Validating package.json...
[2/5] Resolving packages...
success Already up-to-date.
error Command "deduplicate" not found.
$ jupyter lab build  # Build the app dir assets (optional)

As you can see, I’ve installed the yarn-deduplicate package, but jlpm still complains Command "deduplicate" not found.

Any hints for this problem?