I joined a level 10 gym with 60k/50k prestige, which was seemingly a gym fortress. But, in less than 45 minutes, I checked the gym's health and it had been demoted into a level 9 gym with 42k/50k prestige. Was 18k really removed that quickly?
This gym was created by putting 5 Pokémon in the gym. Next, prestige was taken to 50k while leaving all the openings unfilled. Finally, the openings were filled (2k added per addition), which created a 60k/50k gym.
Now, maybe 60k is just being displayed, but not stored as actual gym health. Does that mean that 52k is the max prestige? Or could a gang of attackers really inflict that much damage so quickly?