Immortality/ speed bug

Okay so last night around 12:00 pst we were fighting few teams on dire marsh. There was the big red thing in the sky that comes up and puts that big red zone in the area. Another team was coming out and we flanked them and down an assassin in there. He then was able to crawl around really fast, we could not kill him. He had no execute option above him, nor could he be shot anymore. We then ran to the opposite side of map to exfill so he couldn’t exfoliate with us. Upon filling he was then right there as it let us watch his pov since he was still remaining in the map. Seemed like it was either a bug or Hacks of some sort, but needs to be fixed.