Wandering Trader runs too fast and loses lead to Llamas

When in my Peaceful Survival world, I saw The Wandering Trader. He was walking normally with his Llamas until he ran to my animal pen (for some reason. Maybe he wanted to look at my animals Would be great if they could) and dropped his leads, setting the Llamas free. He didn't look like he was going leash them again, but I saw it as a bug. I don't think he should part from his Llamas.