This has happened with a bear and boar so far.
When the bear starts to run, if it aggros on someone that takes it's direct path into me, the animal runs straight into me and starts moving back and forth in the same tile quickly without going anywhere, and it makes the destroying noise, like it thinks I'm a destroyable object so it tries to destroy me instead of pathing around. It just tries to go through to the other person so it doesn't run or attack me.
The other time it was a boar with someone standing right behind it as I attacked it. It tried to go straight through the person when fleeing, instead of around, and made the destroying noise.