As per: https://getsupport.atlassian.com/servicedesk/customer/portal/11/BBS-89341

We had an issue that was caused by a change made in pipelines:
*Our team had enabled a security feature on the docker daemons to isolate containers with a user namespace.
This update may have affected the build that you're experiencing now.
For more info about the update: https://docs.docker.com/engine/security/userns-remap/

We're currently working on a documentation that will guide you and your team to fix the build.
Once the documentation is ready, we will update it on our infrastructure page and send an email to account's administrators.

Infrastructure changes in Bitbucket Pipelines

Once the update is out, you and your team will have a few weeks to make the changes before we enable the feature on your account.*

We are still waiting for the documentation to be updated here: https://confluence.atlassian.com/bitbucket/infrastructure-changes-in-bitbucket-pipelines-872135046.html

Please advise when this will be done