There could be many reasons, in my case it was node_exporter added incorrectly to shellcmd, that caused PfSense to stuck at boot at configuring firewall in the console view.

The correct node_exporter syntax for shell cmd is:

bash -c "nohup node_exporter >/dev/null 2>&1 &"

What is shellcmd?

Shellcmd is a system utility used to manage commands on a system startup.
You can install it by going to System -> Package manager -> Available Packages -> Shellcmd
Access is at Services -> Shellcmd