Do not have a image but it happens pretty frequently to me. One specific enemy player will be running around without any health bar or "glow" or highlight. This obviously makes it very hard to pick them out from the background and hard to know how low they are. Seems to fix its self after dying and I have not checked if disconnecting and reconnecting fixes it but I would assume so. No clue on what condition causes it, but I know for a fact I've seen it on a enemy seven. Best of luck figuring this one out.