Anchors cutting internet cables happen all the time. It is a weekly occurrence. If you want a visual image: imagine a plane laying down a cable over a forest. It is an heavy cable designed to crash a bit inside the canopy, but it is likely to still dangle in many places.

Another super powerful plane now lays down a one ton hook on a big ass chain and drags it around the forest until it settles on something strong enough to stop it. It does not make the coincidence that big, especially when you consider that many cables land close to commercial routes.