**Steps to replicate the issue** (include links if applicable):
* Go to `https://en.m.wikipedia.org/wiki/Special:CreateAccount`
* Fill in the form and submit
**What happens?**:
* I am on `https://en.wikipedia.org/wiki/Special:CentralLogin/complete?token={redacted}` (desktop site, not mobile)
* I am not logged-in, but the account has been created
**What should have happened instead?**:
* I should have been on `https://en.m.wikipedia.org/wiki/Special:WelcomeSurvey` and I should be logged-in
**Other information** (browser name/version, screenshots, etc.):
* Closely related tasks {T257852} {T318138} with probably same underlying issue, but this task is about the account creation workflow. It is possibly the same issue reported in {T312042} although I don't understand why we are only recently seeing this in production, whereas T312042 was reported in July 2022.
* I see the same issue on eswiki and cswiki so presumably it affects all Wikipedias.
* Sometimes I am logged-in but I am still on the Special:CentralLogin page instead of Special:WelcomeSurvey, and on desktop instead of mobile
* This redirect issue does not happen on desktop domain
* You can look at `reqId:"324772b2-87c1-4245-8264-2c4b1252a8ec"` in Logstash to see debug logs from an account creation attempt on mobile.
{F36957457}