Basic registration form: spam flagged registrations stall without redirection /entry/registerthanks
I was hoping someone could help me debug this issue: I've recently switched from approval to basic registration, and I'm noticing that registrations flagged as spam are stalling at the signup page, without a redirection to /entry/registerthanks. Clicking the "Sign Up" button just shows the activity indicator, and nothing else happens. The dev console shows the request to /entry/register with a 200 OK response, but a content-type of text/html rather than the expected application/json, and no response body is shown in the inspector.
Adding some error_log lines to /dashboard/controllers/class.entrycontroller.log I can see that it gets through the $authUserID == UserModel::REDIRECT_APPROVE test on line 1580 and then into the _setRedirect function on line 935, into the $this->_RealDeliveryType != DELIVERY_TYPE_ALL test and then to the $this->deliveryMethod(DELIVERY_METHOD_JSON); and $this->setHeader('Content-Type', 'application/json; charset=utf-8'); lines... but given the response type is text/html, I guess something is going awry.
Nothing is reported in the web server's error log.
When a registration is not flagged as spam, it redirects to the front page without issue.
I really have no ideas where to look next for a solution, especially given the dev console is doing its typical "This request has no response data available" shenanigans, so.. any hints?