See https://groups.google.com/forum/#!topic/camunda-bpm-users/Xes5msKoNhg

Cause: deploymentId is not set on TimerEntity for timer start events. This causes the job to be acquired even though the process engine has configuration option isJobExecutorDeploymentAware=true

The effect of this bug is that timer start event jobs are always acquired, regardless whether the deployment is currently activated or not.