With the introduction of INFRA-148 platform builds have been parallelized with the -T1C maven option.
In theory, builds that do not depend on each other are run in parallel.
When we run a version's first build (i.e. a new patch or minor/major SNAPSHOT) in parallel, we run into dependency issues (e.g. camunda-qa-db-rolling-update-util requires camunda-engine-dmn but the latter is not (yet) build see here).

The maven configuration of the platform needs to be inspected in order to identify why this dependency is not taken into consideration.

Hint:
The artifacts of the version to be built must not be present in a local / remote repository, otherwise they will be fetched from there and the error will not appear.