The Space Station is thousands of times bigger and throws back a hundred times more light than this will.
Every evening, for most of the populated world, dozens of brighter satellites than this go overhead. I just checked the orbits for my evening here - 57 brighter satellites.
But what about the flashing? Well, we've got those already too. The old, awesome Iridium satellites have giant antennas that act like mirrors. When one beams the sun onto you at night for a few seconds, it's hundreds of times brighter than the Humanity Star. The Hitomi, a failed Japanese weather satellite, flashes every second or so as it spins - again, much brighter than this will ever be.
And worries about Kessler syndrome for this object in a very low earth orbit? Even if every satellite in similar orbit magically exploded tomorrow, the debris would be gone in less than year. In the meantime we could still launch to other orbits. Kessler syndrome is overhyped in general, and a complete non-issue this low.