Why are all the enemies in the Arena unarmed?

so I just started up FEH on my device, and loaded up my cloud data. I was rank 2, and decided to enter the arena. I was below the recommended rank but I didn't care, I entered anyway. I had a low level team (about 1-5), and picked Beginner. I go in, and every enemy is unarmed! I clear it, go in again, same settings, and they're unarmed again! it's weird because this only happened on the easiest difficulty. when I did Intermediate, they had weapons. can someone explain why this happened, or was it just a glitch/bug?