I have noticed that when I use a missile attack against an opponent, instead of it saying their SDI stopped it. IT says my opponent "held their ground". This will happen even when I attack an opponent who has NO SDI research. What is going on?

sdi base is 1.00%

luck bonus also factors into stopping/producing missiles

same thing that you can fail to spy country with 0 spal and you have 100 spal.

Right I hear what you guys are saying. But it doesn't say their "SDI" stopped me. It says their defenses held their ground as though I were doing a conventional attack. When I do the same kind of attack on the primary or tournament server and I am stopped it clearly identifies as the SDI stopping me.

it's a typo that's all.

This issue has been raised on the "bugs and suggestions" forum, but was deemed as very low-level. Besides, the point that your missile failed was still made.