Is it possible this is true with ADT tables as well as DBFs? I think I am
seeing it. The table and the index are encrypted in this case and I have
see messages in the Architect about the table needing to be re-indexed.
Will be upgrading to 8.0.0.8 today to try to remedy.

Per reference 060313-1748:

Product:
Advantage Database Server ( General )
Category:
Bug / Anomaly
Title:
Encrypting Binary Data in a DBF Memo Field Corrupts it
Problem Description:
When storing binary data in a memo field of a DBF, and then encrypting the
DBF, the binary data becomes corrupt. The problem does not occur if a BLOB
field is used.
Solution:
A service update has been done to fix the bug. This is included in version
8.0.0.4 (or later) and 7.10.0.15 (or later) of the servers.