Gym Mon healing?

I have experienced this versus a Raid Boss.

It's a network communication error similar to the dodge bug where health is removed and then restored. Try restarting your phone before you engage in a battle to attempt to reduce this.

The old dodge bug happened because of communication problems between server and client when you tried to dodge an attack. Now it has the same problem with every battle action. It is especially bad when there are more people battling at the same time.

Yes, happens all the time. Best to restart the app before fighting a gym or raid. It's a loading issue and the restart seems to fix, I restart each time I fight because it will start lagging again on the second fight.