No, once I had the site back up I went to the SEO tab on the Persona Bar – in the settings section (the gear), third option down. You could also tweak the setting in the PortalSettings table - I think the setting name is "AUM_RedirectUnfriendly. Obviously, all the normal warnings about modifying settings directly in the database.

Nuts. I'm sorry! I wonder, what do the rest of your settings there look like?

Here's what I had at upgrade when it went successfully:

Concatenate Page URLs - ON
Convert URLs to Lowercase - OFF
Convert Accented Characters - OFF
Set Default Site Language - ON
Redirect to Friendly URLs - OFF
Redirect Mixed Case URLs - OFF

Obviously I may be completely wrong in that this is what solved it. It could probably have been a number of other things — I'm pretty amateur. Hopefully the pros will weigh in here at some point!

I was able to track down the issue for my test website. It ended up being a third party module conflict provided by the theme vendor. The module was updated recently to resolve 9.2 issues. The update was published after I started this test upgrade process.

I started the process again with a fresh copy and installed the 9.2 compatible module and was then able to update to 9.2 without the redirect issue. So my lesson learned is to recheck all third-party modules again for additional updates if you run into update errors.