Deer Running Across the Map on Their Own??? [AoE2 HD][4v4 Black Forest]

So, I played a 4v4 game of black forest in Age of Empires 2 HD edition last week (inb4 someone here advises against it due to its infamous instability 11) and I noticed something strange; at least I don't recall seeing it before: Two deer started running from their initial spawn location all the way across the map from one player to another. Have any of you guys experienced this as well before? xD

Here's two images showing the deer running:

https://i.imgur.com/TlxA110.jpg

https://i.imgur.com/ye9KfGQ.jpg

Also, you can see it for yourself in action in episode 2 of my Road to 1700 ELO on AoE2 HD series if you are interested. It happens right at minute 1.15. Cheers. :)