Oracle 12c RAC: DB has snapshots only on one instance

Hello everyone,

since yesterday we've identified a problem on our DB.

The DB version is 12.1.0.2.0  and runs on a two-node RAC environment (OS: SunOS 5.10).

As we tried to generate an AWR report on the second node we noticed that some snapshots are "missing" or not generated.

With the following statement we've checked the snapshots on the 1. Instance

select instance_number, begin_interval_time, end_interval_time from DBA_HIST_SNAPSHOT where instance_number=1 order by 2 desc;

-->

INSTANCE_NUMBER BEGIN_INTERVAL_TIME

END_INTERVAL_TIME

--------------- ----------------------------- -----------------------------

	1 20.11.17 13:00:55,607	20.11.17 14:00:02,782
	1 20.11.17 12:00:48,342	20.11.17 13:00:55,607
	1 20.11.17 11:00:41,052	20.11.17 12:00:48,342
	1 20.11.17 10:00:33,775	20.11.17 11:00:41,052
	1 20.11.17 09:00:26,512	20.11.17 10:00:33,775
	1 20.11.17 08:00:19,270	20.11.17 09:00:26,512
	1 20.11.17 07:00:12,102	20.11.17 08:00:19,270
	1 20.11.17 06:00:04,769	20.11.17 07:00:12,102
	1 20.11.17 05:00:57,615	20.11.17 06:00:04,769

...

Then on the 2. Instance

select instance_number, begin_interval_time, end_interval_time from DBA_HIST_SNAPSHOT where instance_number=