I've been holding out upgrading to 3.2.2 until I could get this issue resolved and I am hoping I have now and just wanted to share it.
Something happened on my VPS that seems to have resulted in a reverse proxy kicking in with NGINX.
All of a sudden all users were showing as the server IP address and suddenly the exceeding maximum login attempts and do the Google Captcha was appearing every time someone (including myself) tried to log in.
I do have instructions to remove NGINX and the reverse proxy, but I came across this fix in the 3.0.x sub forum: viewtopic.php?p=13038112#p13038112
courtesy of @Noxwizard
I put the change into the startup.php file and the site now seems to be reporting the users actual IP address and not my server.
I was able to log in straightaway without any Maximum Exceeding message etc.
Keeping my fingers crossed that this will be okay.