Honypot login captcha seams to work fine in my tests. Did you change the honeypot input name under Captcha > Modes > Internal > Honeypot? It's possible it's set to something getting filled in by browser auto complete. I don't typically recommend having captcha for login though, which can be turned off under Captcha > Legacy tab. Does this only happen to accounts that have MFA enabled?

but the auto-redirect to the user's Profile doesn't occur.

If you've multiple CB login modules be sure they're all configured properly. Login redirect should always be non-SEO beginning with index.php. Example as follows.

index.php?option=com_comprofiler&Itemid=PROFILE_MENU_ID_HERE

That should safely redirect to profile every time. This assumes you don't have some other redirect taking over. For example CB Auto Actions could potentially redirect away or a 3rd party Joomla plugin could.

Note the login module redirect will not override first login redirect URL configured in CB > Configuration > Registration. So if this is the first time the user is logging in you may want to be sure that parameter is empty or also configured properly to redirect to profile.

Ok, so it sounds like there's an issue with login captcha and MFA. The MFA is probably hijacking the login before the Captcha can properly verify and gets stuck in a redirect loop of some kind. Will have to look into this further, but am unsure if it'll even be fixable as we're limited on how we can interact with Joomla's MFA implementation.

forge.joomlapolis.com/issues/9382

Have added a bug ticket to investigate further, but I just don't recommend using login captcha regardless. It's a legacy implementation for CB AntiSpam and will probably be removed eventually.