The button to raid an alli member is gone if you click on their avatar from the alli chat list. Same thing if you try on a titan results list or war page. The ONLY place it appears in when you go to the main alli page and click their avatar.
I noticed this today. Tried restarting game and device multiple times, on 2 different devices, and 2 accounts. Yes, I have all the game updates. A few in my alli have this problem, the rest are fine. Same in another alli.