These CSS rules:

.device .remarkup-assist-button,
.device .remarkup-assist-separator {
   display: none;
 }

...in webroot/rsrc/css/application/conpherence/message-pane.css are too broad. The Conpherence CSS is being pulled onto other pages (probably by the persistent chat popup) and these rules are applying everywhere. Here's the inspector in Safari:

I don't immediately see any recent change responsible for this, although I haven't tried to bisect; I suspect the culprit is something mundane and Celerity-related, not an actual CSS change. But we should fix the rules, since any CSS should be able to be included safely on any page without changing the display style.