Aggroed polar Bear hitting from outside walls

The Polar bear can hit you from approximately one block of distance even if outside a building or wall:

I was playing a survival world in the snowy biome, in a village when out of a sudden a bear hit me trough the wall of a house, and I discovered that

it had a cub so it was naturally aggroed from the spawn. I tried to replicate the bug with another bear and I hit it to aggro it and the result is the same