Oracle Multimedia goes invalid on Downgrade 18c >> 12.1.0.2

Oracle 18c Std Ed 2

Oracle Linux 6

As part of my upgrade preparations, I like to document and practice a downgrade, though fortunately I've never had to actually use it.  In the current exercise, I have a database that was upgraded from 12.1.0.2 to 18c.  At several steps during the upgrade process, including the last sanity check, I run the following:

select substr(comp_name, 1, 45) as comp_name,       substr(version,1,8) as version ,       substr(status,1,10) as statusfrom dba_registry;

This database, actually having started life at 10g , and upgraded through 11.2 to 12.1, - and being Std Ed. - I expect some  advanced options to go from 'VALID' to 'OPTION OFF".  But on the downgrade back to 12.1.0.2, I saw something I didn't expect.  That is, that  Oracle Multimedia went from VALID to INVALID.