Couldn't reproduce, but the emoticon button for main posting fields was missing anyway. I've fixed that, so I wonder if the issue was somehow you had to paste in the emoticon from somewhere - pasting is notoriously problematic, as it carries styles with it - probably vertical-alignment in this case.
Screenshot is from Compo.sr website, assumed it would be relevant to main release too. I didn't have to paste, I typed :) and it automatically converted it into an emoticon. When going back to edit that post, I saw the alignment for the emoticons was off somewhat.
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#2526 - Editor issues with emoticons
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