macos non root user not able to initiate tcp connection

Recently my system started behaving strangely.

When connected to CCTV network (WiFi without a route to the internet) TCP connections seem not to work for non-root user.

woody@progress : ~$ nmap 192.168.111.76
Starting Nmap 7.92 ( https://nmap.org ) at 2022-05-06 16:01 CEST
Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn
Nmap done: 1 IP address (0 hosts up) scanned in 0.07 seconds

They, however, do work for root.

woody@progress : ~$ sudo nmap 192.168.111.76
Starting Nmap 7.92 ( https://nmap.org ) at 2022-05-06 16:01 CEST
Nmap scan report for 192.168.111.76
Host is up (0.0092s latency).
Not shown: 994 closed tcp ports (reset)
PORT     STATE SERVICE
80/tcp   open  http
443/tcp  open  https
554/tcp  open  rtsp
1935/tcp open  rtmp
6001/tcp open  X11:1
9000/tcp open  cslistener
MAC Address: EC:71:DB:3D:74:B6 (Shenzhen Baichuan Digital Technology)

Nmap done: 1 IP address (1 host up) scanned in 13.54 seconds

When connected to my usual network (WiFi with a route to the internet) then, TCP connections work just fine.

What might be causing this?

What's the best way to debug it?

I am running:

macOS Monterey Version 12.3.1 (21E258)

A native firewall is disabled as I am using LittleSnitch Version 5.4.1 (6256).

The behavior is the same regardless of LittleSnitch Filter Mode (Disabled, Enabled, Alert, Allow).

The same setup worked well a couple of weeks ago.

I did update from 12.3 --> 12.3.1 recently, but I am not sure if it is related to that.