I don't wish to confuse the issue but the problem displayed in your screenshot image is not the same as the bug detailed in the OP.
This bug thread details a problem posting two emoji in a row which seems to have been fixed
What your image appears to show is that after entering one or more consecutive emoji, the cursor always parks to the left of the emoji and that problem is still present in the currently deployed build.
Windows 10 version 21H2 Firefox version 97.0 (64 bit) Xenforo version 2.2.8 To reproduce; type a word in the editor, add a smiley. The cursor remains to the left of the smiley. Clicking to the right of the smiley has no effect.
[EDIT] For clarity, both bugs relate to Firefox users.