Since 27-02-2019 our Frontend UnitTests fail in Bitbucket pipeline with the following error:

Testing GD.ProgramProcessing.WebUI...
yarn run v1.12.3
$ ng test --single-run --no-progress --cc
(node:77) DeprecationWarning: loaderUtils.parseQuery() received a non-string value which can be problematic, see https://github.com/webpack/loader-utils/issues/56\\
parseQuery() will be replaced with getOptions() in the next major version of loader-utils.
28 02 2019 10:41:15.582:INFO [karma]: Karma v1.7.0 server started at http://0.0.0.0:9876/\\
28 02 2019 10:41:15.584:INFO [launcher]: Launching browser ChromeHeadlessNoSandbox with unlimited concurrency
28 02 2019 10:41:15.805:INFO [launcher]: Starting browser ChromeHeadless
28 02 2019 10:41:16.209:ERROR [launcher]: Cannot start ChromeHeadless

28 02 2019 10:41:16.209:ERROR [launcher]: ChromeHeadless stdout:
28 02 2019 10:41:16.209:ERROR [launcher]: ChromeHeadless stderr:
28 02 2019 10:41:16.372:INFO [launcher]: Trying to start ChromeHeadless again (1/2).
28 02 2019 10:41:16.745:ERROR [launcher]: Cannot start ChromeHeadless

28 02 2019 10:41:16.745:ERROR [launcher]: ChromeHeadless stdout:
28 02 2019 10:41:16.745:ERROR [launcher]: ChromeHeadless stderr:
28 02 2019 10:41:16.971:INFO [launcher]: Trying to start ChromeHeadless again (2/2).
28 02 2019 10:41:17.199:ERROR [launcher]: Cannot start ChromeHeadless

28 02 2019 10:41:17.199:ERROR [launcher]: ChromeHeadless stdout:
28 02 2019 10:41:17.199:ERROR [launcher]: ChromeHeadless stderr:
28 02 2019 10:41:17.408:ERROR [launcher]: ChromeHeadless failed 2 times (cannot start). Giving up.
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
Unittests failed

The code for running the UnitTests hasn't been changed for months. Has there been changes to Bitbucketpipelines in the past few days?

We need to create a new release for our client but we can't right now. Please understand that this is urgent.

Kind regards,
Kevin Brok
Whyellow