rman Ora-4031 - how to flush large pool?

We have a system that is throwing ORA-4031's in rman archive log backups after the system has been up a few days. To my understanding, RMAN tries to use the large pool for it's activities. When we alter system flush shared pool - the errors do not stop - the database has to be bounced or the large_pool has to be increased 3M or so. Does alter system flush shared_pool flush the large pool? If it does, then why would that not defragment the pool? If it does not, is there a way to do it? In general, will flushing the shared_pool defragment it - large pool or otherwise?

Thanks,
Doug C.

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