I'm noticing the same thing with version 3.0.4. For me, prior to updating, the emoji icon was present and functional on firefox and IE/Edge browsers, but not on Google Chrome. Now it's nowhere to be found on any of those browsers and the reports we submitted to the bug tracker concerning the matter have mysteriously vanished. It would be nice to get an explanation from Jason.
We are having the same issue. After upgrading to latest AC we started to get complains from the users that the emojis are gone or just show an empty circle. This is been going on for several months now. Hopefully somebody can find a solution.