Here  is a patch that fixes the reported problem.

A minimal reproduction test:

(ert-deftest totoro ()
  (set-buffer "*scratch*")
  (insert "setq")
  (setq next-error-recenter '(4))
  (occur "setq")
  (next-error))

It seems that occur-mode-goto-occurrence should be called after
restoring the original buffer.

Nathan