HAProxy + Regional Servers + Shibboleth

I am able to capture the room parameter and stick it in a table. With this setup all future requests with the same room name will be redirected to the same backed.
The challenge that I am facing with the shibboleth authentication is the following

Lets say the room name is “TestRoom”
When enter the URL in the browser jitsi.example.com/TestRoom, HAProxy sees this request ClientIP:443/http-bind?room=TestRoom
The name TestRoom gets added to the table and then I can make decisions with this information (for example sending the request to a specific backend)

When I get challenged with shibboleth auth, I click “i am the host” and this url gets generated:
ClientIP:443/login/?machineUID=655c27f&room=qweqwe@muc.meet.jitsi&close=false
this url has also the room url parameter but has the “@muc.meet.jitsi” in it, so pattern doesnt get matched and the request gets send to a different backend.

This is the acl rule I am using
acl sticky_room url_param(room),in_table(Web-Servers)