Nothing like hitting the gym when you are there by yourself. Then all of a sudden you see someone who seems to be a little hostile. Before they take the gym over, you try your best to keep it yours for the time being. Only to find out, instead, you helped the other person out in the long run.
A trainer happened to experience this bug. What happened was he was trying to force the opposite team member who was attacking the gym at that time to battle more than once. This trainer tried prestige the gym up, while the other was trying to take it down. Something happened, though, that helped the opposing member out.
The gym had already been taken over by the other team. What happens to the prestige points though? Most would think that the trainer would just lose them, just as he had the gym. That didn’t seem to be the case, however. Instead, the newly taken over gym had gained 159 prestige points. Which was the amount the trainer said they received.
Want to prestige enemy gyms? It may be a bit complicated, but this is how it’s done. It’s hard to say rather or not this is an actual bug. Or if it’s just an exploit to something Niantic didn’t think would come about. Either way, this could be useful if you have friends on different teams.