This might be a bug too. I thought you were supposed to be able to surround a wormhole with force fields so that the AI warps into the hole in the middle, and is stuck there. Instead, they're flying at the field and popping right out on the other side. There are also very few ships, the hole isn't getting filled and forcing the extra units out. These are the force field buildings, if that matters, not the ship.
Also, a weird one. I forget what they're called, but the unlimited range heavy artillery unit that gets weaker in numbers, and it says ideally to have only 2 at a time. An AI homeworld spammed them, which at first was no problem due to their drastically reduced damage. Then, at some point and with no visible differences, I started losing maybe 100 ships per second. Is it possible that with too many of them in one system, that weakening effect stops working?