I have those fonts installed, but whether The way you produce the crash is to visit a file with C-x C-f.
;; Commenting this line is makes the crash go away, 'prepend also makes the crash go away(set-fontset-font "fontset-default" 'unicode "Apple Color Emoji" nil 'append)
(require 'all-the-icons)
;; This is the actual culprit. Even with 'append, not inserting the icon into the mode line
;; after change major mode will not produce a crash.
(add-hook 'after-change-major-mode-hook
(lambda ()
(let* ((icon (all-the-icons-icon-for-mode major-mode))
(face-prop (and (stringp icon) (purecopy (get-text-property 0 'face icon)))))
(when (and (stringp icon) (not (string= major-mode icon)) face-prop)
(setq mode-name icon)))))