I just find out this unlucky accident. The first picture indicates the initial position of asteroid, Lava planet, and metal planet. The second picture shows the path for asteroid to attack the metal planet. My team already get every planet except the metal planet, so we send the asteroid to destroy it. The third figure displays the orbit of the lava planet. Few seconds later ... What the .... We lose one commander on the lava planet. Fortunately, my team is a shared army. One of our commander is still alive on another planet.
It's not a bug, it's a feature. Remember you have the red line to show you where the planet is heading, and you can cancel it at any time to stop the planet moving. This allows you to create maps where a target planet might be in the middle of the solar system, but be 'defended' by having lots of other orbital bodies in the way, making it difficult/risky to try and smash, you might have to 'clear a path' with other asteroids first. It's also just hilariously funny when someone fails.
should get at least a kind of ETA thing with a warning of a planet/asteroid passing another planetoids route ..
If I have the technology to launch a planet out of orbit and target another planet with it as a weapon, why would I lack the technology to validate my launch path?
If I recall this was something a lot of people asked for, and I'm not gonna complain and ask for it to be removed.