It appears Poland was the target, so it was done on purpose. Some of these drones didn't had explosives in them but had extra fuel instead to increase their range to reach deep into Poland. They eventually ran out of fuel and landed/crashed.
Other drones, longer range ones with explosives, turned around and continued to Ukraine.
At first I thought they were after some weapons in transit to Ukraine, but later it seemed it was not so.
Some did get shot, but with very expensive rockets. Sure, they had to... but if Russia starts sending 100's each day this won't work.
Expensive rockets and planes which are also expensive to fly.
I think I've read some drones reached 300 km away from the border.
They say Russia is testing NATO defenses, but I don't understand.
Russia alone is not able to fight at the same time in Ukraine and some NATO front.
They just gave the NATO plausible reason to patrol the western Ukraine skies,
so that Ukraine can deploy more air defense eastwards.
So Russia either intends to grow relunctance of NATO to send air defenses to Ukraine (and use them themselves, so Putin may think the NATO can't also not help Ukraine and fight at some other front at the same time)
or counts on other countries to help Russia (North Korea already, then Belarus, and the big question is how much would China help, how much is at stake for China in Europe).