Health bars disappearing [bug]

Okay, I didn't get a screenshot sadly, but if you look at my game log, you can see that I've had to periodically leave games for awhile now. Anyway, I've had everyone's health bars disappearing, which makes playing properly quite difficult for me. As a support, it is particularly trying because it's hard to keep someone alive when you can't tell when they're about to die. I have adequate ping, excellent FPS, and a new (less than one year old) laptop with 16 GB of RAM and a 4 GB graphics card. If there's some magic fix, I'd love to know it. I am not sure how I could reproduce the specifics of the bug, but all the same, it makes playing a lot less fun