Glitch on HP

I went to a park and took down a couple of gyms with a family member and we each put in mons. By the time I got home, another team was already taking them down. One was down and the other being attacked. The one being attacked is close enough to home I could still see the gym in the game and watched as it went down and turned color. The game notified me that my mon had returned from battle. I went into power it a half level and save a revive but the game showed it with a full health bar. So I closed the app and went back in 5 minutes later and still a full health bar. However, if I go into items and select revives to use it identifies the mon as needing reviving even though looking from the mon's view it as a full health bar. I powered up a half level and the game showed a CP and HP gain but going into items again, it is identified as a mon that needs reviving and not healing, a status that should normally change after a power up.