Performance issue - Library cache lock

We are seeing one of our database nodes flooding with "concurrency" wait i.e "library cache lock" and when going back to the start of the wait in ASH we are seeing the blocking session actually seems to be from one of the export sessions and it's from SYS too. The two sqls which were captured in ASH from that session are below. The second one is the one spending time on an event "reliable message" with current_obj# showing s '-1' and blocking others now. When we see the start of the issue, that session was showing current_obj# as index "AQ$_PROPAGATION_STATUS_PRIMARY" for quite a long time. Are there any bugs associated with such an issue? This table seems to be streams related but we don't use streams in this database, so not sure from where it's popping up.

 BEGIN   SYS.KUPM$MCP.MAIN('SYS_EXPORT_TABLE_02', 'SYS', 0, 0);  END;  BEGIN sys.kupc$que_int.delete_queues(:1, :2); END;

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