If you left it for a while before sending in the transports the planet could have been building defenses the entire time, which could explain the damage done to your fleet.

Finnian, the best way to get around the problem of parts of your empire randomly leaving are choosing the law and order doctrine, and having large amounts of imperial guards on every sector capital. Tens of thousands preferably. Arkheias, different planet types and development levels are good at pro...

Finnian, did you have a large empire? In large empires sector capitals can randomly leave your empire and take planets with them, although imperial guards on sector capitals are supposed to stop this.

Did you take Aglamun originally? That planet was a sector capital, and worlds around that sector capital will sometimes join you empire if you take the sector capital they are close to.

It creates a complete map of all the regions you have explored in a 6200x6200 pixel image. However, it is extremely CPU intensive, so you'll need to use a reasonable powerful computer to generate it.

If you want to make a map of the entire game world you don't screenshot your monitor. Anacreon has a built-in function to make a map by clicking the galaxy in a square button on the top left of the screen.

I'm not entirely sure if this is a bug, but it is possible to make starships travel around the central nebula by taking a detour far outside of the map.

Sector capitals of the trade doctrine do not import trillum, even when it is needed by other worlds connected to it.

After attacking an enemy empire I took its capital. However, after being captured it retained the "capital" designation (not sector capital) and remains a different doctrine. It also does not allow planets to be controlled, unlike a normal capital.

Imperial might seems to be stuck at 100 permanently, however, the imperial might of others is visible. This also happens across different computers and browsers.