Unable to link a github repo in snapcraft.io

I’m trying to link the github repo for a project to be automatically built/published as I’ve done before. The account linking works, the list of orgs/repositories populates fine, but when I select the repository it fails to validate. The text box turns red and is no longer editable after this.

It looks like the value isn’t actually being passed to the api for validation. In the network calls I see a 500 error on https://snapcraft.io/api/ami-deprecation-tool/builds/validate-repo?repo=undefined