2fa stage couse "No identification data provided" after udated to 2025.12.1 from 2025.10

### Describe the bug

As continue to https://github.com/goauthentik/authentik/discussions/19519

### How to reproduce

1. Using default auth flow + NPM + Cloudflare Proxy
2. Log to : auth.mydomain.com
3. After password stage ,instead of MFA stage got : `No identification data provided.`
4. On mobile sometime 2FA page available but after entered code ,reload to 1st stage.

### Expected behavior

Should work as before: MFA stage -> Login

### Screenshots

### Additional context

From: `https://auth.mysite.com/api/v3/flows/executor/default-authentication-flow/?query=next%3D%252F`

- Nginx proxy Manager:
```
# ------------------------------------------------------------
# auth.mysite.com
# ------------------------------------------------------------

map $scheme $hsts_header {
https "max-age=63072000;includeSubDomains; preload";
}

server {
set $forward_scheme http;
set $server "10.0.0.13";
set $port 9001;

listen 80;
#listen [::]:80;

listen 443 ssl;
#listen [::]:443;

server_name auth.mysite.com;

http2 on;

# Custom SSL
ssl_certificate /data/custom_ssl/npm-5/fullchain.pem;
ssl_certificate_key /data/custom_ssl/npm-5/privkey.pem;

# Asset Caching
include conf.d/include/assets.conf;

# Block Exploits
include conf.d/include/block-exploits.conf;

# HSTS (ngx_http_headers_module is required) (63072000 seconds = 2 years)
add_header Strict-Transport-Security $hsts_header always;

# Force SSL
include conf.d/include/force-ssl.conf;

proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $http_connection;
proxy_http_version 1.1;

access_log /data/logs/proxy-host-6_access.log proxy;
error_log /data/logs/proxy-host-6_error.log warn;

location / {
#set_real_ip_from 192.168.0.0/16;
set_real_ip_from 100.64.0.0/10;
set_real_ip_from 172.18.0.0/16;
set_real_ip_from 172.19.0.0/16;
# NPM generated CDN ip ranges:
include /etc/nginx/conf.d/include/ip_ranges.conf;
real_ip_header CF-Connecting-IP;
real_ip_recursive on;

proxy_set_header Host $host;
proxy_set_header X-Forwarded-Scheme $scheme;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header X-Real-IP $remote_addr;

proxy_pass http://10.0.0.13:9001;

# Asset Caching
include conf.d/include/assets.conf;

# Block Exploits
include conf.d/include/block-exploits.conf;

# Force SSL
include conf.d/include/force-ssl.conf;

# HSTS (ngx_http_headers_module is required) (63072000 seconds = 2 years)
add_header Strict-Transport-Security $hsts_header always;

proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection $http_connection;
proxy_http_version 1.1;

}

# Custom
include /data/nginx/custom/server_proxy[.]conf;
}
```

### Deployment Method

Docker

### Version

2025.12.1

### Relevant log output

```shell

```