Very strange,  I have done many invasions and have not seen your problem.   You might want to open a ticket and send your save game (or put a link to your save here)

well i guess that's progress

I have also been having this issue.  Any solutions yet? 

Hi,

I've always placed all of my legions on the same tile - or split them between two if there's an extra city - and haven't had any problems at all.

Cheers,

Jon

Same thing here. No matter what I do I just can't take the planet.  Overwhelming forces, tech researched to max etc.  Lycan371, will take your idea, hopefully this will help, thx.

Ok got my battles working. I have not done an invasion yet, but I discovered that if things are a bit desperate, just place ALL your troops on the Capital city tile and you should win even with inferior (2-1) numbers, unless the enemy numbers are truly overwhelming. This makes a lot of sense since the Defender usually always has the advantage in a straight streets city siege.

Now if you`re attacking the reverse is likely true (if the Devs kept it realistic), which would mean you need THREE times the number of attacking troops at least to win a ground battle. I`m sure Tech levels affects this.

I lost a fight where my relative power was listed as something like 1893475373843743 to 1

I heard someone say that besides the odds of wining an invasion, there's a mini-strategy on the battlefield that you must consider to ultimately win. So there is a strategy on placing your legions on the battlefield or else we would not have that option, and this is regardless of your odds. You favorable odds only gives you an advantage but you can still lose. Now I might be wrong and there might still be a bug. I also had a battle that I lost once when I had an advantage, but it doesn't happen often.