There is some possibility that these drones were jammed by Ukrainian REB systems and they accidentally went into Poland.
But I think it's not very likely. Russia is just testing Poland's reaction. And IMO, reaction wasn't great. There is different numbers, but most resources says that Poland managed to shoot down only 4 drones from 19. And they used very expensive rockets for these cheap drones.
And I'm afraid that after this attack nothing won't change. I don't believe that Poland is going to start shooting drones in Western Ukraine.