“I get a 404 error when clicking e.g. create group… I then get redirected to the correct page, when I click create group button after filling out the form I get the same 404 error, and then get redirected to the newly created group page”
I am having exactly the same problem.
I am clicking a link such as view a status update and it is throwing a 404 error. It is then redirecting to the correct page. I think it is something to do with permalink structures.