I noticed that too.
While the AI in general seemed to be beefed up a bit, there was this odd behavior.
They acted as if they expected the tower to heal them.
Now, I could understand if they were supposed to be using the damage of the towers as a defence, but when they are that low on health, it's worth the risk to run in and finish them off. (or if you are ranged, you don't even have to run in)
IMO, they should use the towers to their advantage, but if their health is too low, they need to teleport/run back to their base to heal if they don't have an item to heal.
