Backend maxconn not working


I have multiple instances of HAProxies and I’m trying to limit the total connections on the backend servers. The issue is that, even though I’ve set the

    server worker1 tfo check weight 10 maxconn 300

The current sessions established on that backend are way over 300 (reaching 1.5k sometimes).

I tried to do this on HAProxy 2.2, 2.4, 2.5, the behavior is the same. Any ideas why?

Thank you.