[BUG] Disappearing health bars

I haven't heard anyone else mention this so I'm wondering how many people experience this bug. So you hit tilde a few times to get to the selected health bars you want to see. I always go for the one where the only health bars visible are the ones over demigods' heads- makes it easier to spot their health among the chaos. Thing is, from time to time random demigods' (both allies and enemies) health bars will just vanish from over their heads. I can't see the bars at all and have to mouse over them to see their health. That's extremely inconvenient and aggravating. Sometimes a little later in the game they'll pop out of the fog and they'll have health bars over them again. But I can't see a pattern to it. Dunno if anything specific causes it to happen each time. Anyone else seeing this happen?