It's hard to tell what's going on as long as we can not reproduce the problem (deterministically).

ok apparently ^R doesn't work quite the same in Fundamental mode. this was my clue: CRM Buffer Size Mode File . .e 2933 Fundamental /tmp/.e .emacs 2933 Emacs-Lisp /tmp/.emacs so, i expect this will help: (setq-default major-mode 'text-mode) it does seem evil definitions are active in Fundamental mode, but perhaps undo-tree isn't?