I could see several bugs logged for this issue. Please log an SR with Oracle support to diagnose this further.
The issue seems to be from DB side and an SR would help you in resolving the issue.
However, added below few points you can look as well from your side.
+ DB may be core dumping in which case it would be required to resolve the core dump issue.
+ Running ASH report from sqlplus may not be working in which we need to resolve the DB side issue.
+ If feasible you can choose to upgrade DB to higher version.
Found a similar issue which was analyzed in Bug 13498473 - DATA NOT DISPLAYED ON ASH ANALYTICS PAGE IN 12C CLOUD CONTROL , during triage it was found that the issue was resolved by first upgrading the 10.2.0.4.0 DB to 10.2.0.5.0 DB and then applying the latest DB PSU patch , so I would recommend if its possible to first try a DB upgrade to min 10.2.0.5.0 (with Latest DB PSU )
Thanks for your reply.
I will suggest the customer as you suggested.