> Reproducing this is random for me but many times a day recently.
> Alternatively, here is a contrived recipe to reproduce this error, but
> *not* using global-auto-revert-mode, instead purposely putting a dead
> buffer in auto-revert-buffer-list.  I think it still hits the same
> code path inside auto-revert-buffers.
>
> ~~~~~~
> (require 'autorevert)
> (let ((buf (generate-new-buffer "foo")))
>   (push buf auto-revert-buffer-list)
>   (kill-buffer buf)
>   (auto-revert-buffers))

This recipe fails earlier, in the lambda form checking remote buffers.
I've fixed this case as well.

Could you pls check whether the patch works for you with magit? (I
don't use magit myself)

> Regards,
> Dale

Best regards, Michael.