Signing in with social (Google, Facebook) throws error "Already found an entry for username"

Currently seeing this issue with the presignup trigger.

Cognito allows you to create social accounts that are disconnected from a cognito native accounts (but with the same email), so to solve that we're automatically creating a cognito native account in the presignup trigger and linking it.

However, when we do this, the first call to authenticate fails with "Already found an entry for username...".

Attempting to login again previously worked as a super hacky workaround, but now even that seems to not be working.

What's going on with this system? We've been using it in production for probably 3-4 years now, and almost have an entirely AWS stack. The difference between EC2 or RDS and Cognito is night and day. There's been almost 0 new features, and there's a massive backlog of issues being raised on forums and on AWSAmplify that are directly related to the Cognito backend.

Can we get an actual response other than "it's on the roadmap"? There's questions about this dating back to 4 years ago, and somehow this isn't even mentioned in the documentation yet.

By the way, here is a fantastic post on a bunch of other issues. Surprise surprise, this ones listed there too:

https://www.reddit.com/r/aws/comments/m77p5g/aws_cognito_amplify_auth_bad_bugged_baffling/

For the record, we're actively looking to move away from Cognito, and we'll likely be taking several other parts of our stack along with it. The product has a lot of potential, but all the problems you need to work around can turn an hour long task into an all day debugging session.

For anyone finding this post that is at the early stages of their Cognito journey I would highly recommend looking at something like Auth0 instead. Don't be fooled by the price, you get what you pay for with Cognito (which is basically nothing)