Here we see the first of several cases in the book of Ether where Joseph Smith, in his editing for the 1837 edition, removed the do auxiliary. Besides this one here in Ether 11:5, there are three more:
For the example in Ether 11:10, Joseph added the past tense marker -d but forgot to delete the did, with the result that the 1837 edition missed implementing this change. The change in Ether 11:14, of did do to did, involves the main verb do. Attempts by Joseph to remove instances of did do can be found elsewhere in the text (see the discussion nearby under Ether 11:14).
Otherwise, the removal of the do auxiliary for other main verbs was fairly rare in Joseph Smith’s editing for the 1837 edition. Besides these examples at the end of Ether, there are only four more elsewhere in the entire text (here I exclude the cases of “do/did do” referred to under Ether 11:14):
Note that three of these are in 1 Nephi, at the beginning of Joseph’s editing for the 1837 edition. Otherwise Joseph did not edit instances of “do/did pass” (10 cases), “do/did set” (3 cases), and “do/did confound” (7 cases). Similarly, with respect to the edited examples here in the book of Ether (again I exclude the case of “do/did do”), other instances in the text of “do/did cause” (48 cases) and “do/did cease” (17 cases) were left unchanged in Joseph’s editing for the 1837 edition.
In the critical text, of course, for each case of the do auxiliary we will follow the earliest reading. In each of these instances of idiosyncratic editing for the 1837 edition, the original do auxiliary will be restored.
Summary: Restore in the book of Ether the original periphrastic past-tense forms involving the do auxiliary that Joseph Smith removed in his editing for the 1837 edition; in particular, did cause will be restored in Ether 11:5 and did cease in Ether 13:22.