Error updating user preferences. Credentials not provided?

Looking at the logs I can get as far as requesting a user’s badge assertions then I am logged out.

Here is a gist showing what I can see https://gist.github.com/vicnete/143e8fab73137f37b6aadebea37dd35e

After a while it works and both of the requests include the username.

I am trying to figure out:

What may be causing this?
Why is it fixed after about 8 minutes?(some sort of user cache that logs me out when it is inconsistent is my best guess at the moment).

I have an idea of a fix for my situation, there is a solution manually and we could replicate what that solution is calling every time we issue a badge, but we need to get rid of the 8 minute/similar time cache.

Asking our users to wait around for 10 minutes before accessing their profile after earning a badge seems less than ideal.