The new Opera comes with an ad blocker that is set to "on" by default. I don't see any active blocking of .swf files.
Problem is that ad blocker is blocking not only ads but every HTML5 CreateJS file.
It doesn't seem to be exclusive to Animate or CreateJS. I just downloaded Opera and tested some Sizmek preview links for some banners I've made... both hand-coded with HTML/CSS/GSAP, and with Animate/CreateJS. All of them are showing the static backup image instead of loading any animation.
When I preview any of those banners in Opera locally (or on my own test server), they load fine though. I'm on a Mac (OSX 10.10.5) and this is in Opera 38.0.2220.41 by the way.