With the help of the HPRC, we solved our problem with Gateway redirects by correcting an error in our Neighbor Gateway IP addresses.
Running NETTOOL.NET.SYS helped us find the error:
:nettool.net
>>nameaddr
>>routing
>>routing
gave us a (long) list of the active routing table, and helped us see which IP addresses were being routed incorrectly.
After we corrected the problem,
NETTOOL, nameaddr, routing, routing
shows ONLY the Neighbor Gateway entries that we configured.