Weird Queue Time With TCP mode

Hello there

I have setup mqtt load balancing with HAProxy and see some weird log
Nov 4 10:19:41 localhost haproxy[3489]: [04/Nov/2020:10:19:08.869] ssl_fnb_mqtt~ ssl_fnb_mqtt/fnb_mqtt 33059/0/+33058 +0 – 1418/17/17/17/0 0/0

I don’t see how the connection is queued too long while we have just a few connections and have no limit for backend and servers

According to the document
“- Tw: total time spent in the queues waiting for a connection slot. It
accounts for backend queue as well as the server queues, and depends on the
queue size, and the time needed for the server to complete previous
requests. The value “-1” means that the request was killed before reaching
the queue, which is generally what happens with invalid or denied requests.”

I don’t see how it is possible for queue time here. Please hep me to clear that out. I’m a little bit concern to scale it out due to this problems.

Thank you in avanced

someone help please