magento2: Can't deploy with multi-threading + compact mode

Preconditions

1. Magento 2.4.3-p1 (also tested on 2.3.4)

Steps to reproduce

1. Create a first theme as child of Magento/blank
2. Create a second theme as child of the first theme
3. Create a CSS (can be empty for the test) in the parent theme’s web/css folder
4. Try to deploy the child theme’s static content with multi-threading and compact mode enabled :

rm -rf pub/static/frontend/ pub/static/base/ \
var/view_preprocessed/pub/static/frontend/ \
var/view_preprocessed/pub/static/base/ && \
php bin/magento setup:static-content:deploy -a frontend -t Customtheme/subtheme -f en_US --jobs 4 -s compact --no-less

Expected result

1. Both themes are deployed

Actual result

1. Multiple errors are triggered during the theme deployment (see screensot bellow)

You can find attached to this issue the two sample temes created without anything inside but the required files and the empty CSS on the parent theme.

sample-theme.tar.gz

Also i’ve used the official Magento Cloud Docker images to reproduce this bug.

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• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
• Severity: S2 - Affects non-critical data or functionality and forces users to employ a workaround.
• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.