Flash should work. Uninstall and reinstall just Flash.
Tried that and tried uninstalling and reinstalling different browsers, with ICS twitch streams that played fine at 720p/1080p are now having problems going above 10fps at 480p or lower and some just bug out. Don't know if it is specifically ICS or the updated Flash player for ICS, also have had some weird graphical bugs pop up in other apps like weird flickering in the Youtube app's homepage.