It seems that upon dump & restore, UPPER indexes either aren't recreated
correctly or not listed somewhere the query analyzer can know it exist.
I've encountered first encountered this problem doing an upgrade to
7.3.7 to 7.4.6. I again encountered this program replicating a server
(same 7.4.6 on both source & dest). Dropping the index and creating it
again seems to fix the issue.
This server isn't slated to go live for another few weeks so I can leave
it in this semi-crippled state for some debugging/testing if needed.