Updated FoolCraft with the 2.4.1 version of BlockArmor, try to connect with a matching client and the client gets immediately booted. I unfortunately cannot provide my log at this moment but I could reproduce the problem if need be. I didn't crash the server or my client so all I would be able to show would be what I see in the logging in my client. Hopefully, that will be enough to point you in a direction.

Fixed in v2.4.2, thanks for telling us!