Have been building without issue, and then this morning they spontaneously began to fail continuously fail with:
Fatal error: Uncaught Error: Cannot call constructor in /opt/atlassian/pipelines/agent/build/vendor/symfony/finder/Comparator/DateComparator.php:48
The issue could be related to changes in your source code, dependencies, or the Docker image you use for your builds.
I would suggest debugging this locally with Docker first to figure out if that's the case. If the build fails with the same error locally, then the issue is most likely not related to Pipelines, and you can debug this locally without consuming Pipelines minutes.
You can find step-by-step instructions on how to debug this locally in my reply to another question here:
It's important to use a clone of the repo at the commit with the failed build, and also use the same Docker image that you use as a build container for the failed step.
You can create a ticket with the support team and provide the URL of some of the builds that fail and some of the ones that succeed, so we can look further into this issue. If there is a support ticket open, the engineer working on your case will be able to access the builds and additional logs in order to investigate.
You may still be asked to debug one of the failed builds locally, as that's usually the first step in determining if the issue is likely to be caused by pipelines or not.
You can create a ticket via https://support.atlassian.com/contact/#/, in "What can we help you with?" select "Technical issues and bugs" and then Bitbucket Cloud as product.