BPServiceActor#blockReport has the following check:
Many tests trigger an immediate block report via BPServiceActor#triggerBlockReportForTests which sets lastBlockReport = 0. However if the machine was restarted recently then startTime may be less than dnConf.blockReportInterval and the block report is not sent.
Time#monotonicNow uses System#nanoTime which represents time elapsed since an arbitrary origin. The time should be used only for comparison with other values returned by System#nanoTime.