If that doesn't help, then I am sorry - hopefully someone else can help who had different scenarios... :-)
Thanks a lot for the suggestions, I appreciate it.
Interestingly, when I do create a new account, the new user sees the default front page and cannot access any of the content they create. This is even when I get them the required permissions. The content they create appears when I log in as a user created before the update.
No errors appear in the logs!
Tim