Also possibly related since both involve constant health loss, but sometimes HIVE's overheal gets bugged and will stop degenerating for a while. It doesn't take too long to take damage back to normal, but it does make it harder for her first 2 weapons to do any damage during that time.
About HIVE's overhealing (or overhealing, in general terms), it's usually confusing to many players (maybe we should clarify it somehow). Thing is, max health is what decreases over time, so you will only see your current health decrease if you are full. However, if you are hit, actual health is below your max health, which keeps decreasing, but it's not at your sight anymore. When max health reaches your current health, you will see it decrease again.