I’ve read a bit more about this.
It happened in Russia. The spear thrower allegedly didn’t intend to actually hit it, rather just give a cool shot for the camera. He offered to pay for the damage (it’s not clear to me whether the drone operator accepted). The drone operator was chill and suggested that a competition for slaying winged demons from the future should become an annual feature at the re-enactment.
Oh, and the event organisers shat themselves and immediately went into “issuing statements” mode. 😀