I just discovered this morning that one of the developers had created
an index on a field with about 50 values on a table that for some
customers, has 10's of millions of records. In the test database I
use (5.2GB), the longest duplicate chain had over five million
entries.

I've seen posts talking about the dangers of long duplicate chains,
and bugs in this area with older versions. This problem is in a
program version whose customers are using InterBase 5.6. Is it
possible that database corruption could result from these chains
being so large?