In the original manuscript for 1 Nephi 11:27, the past tense was used for each verb in the two clauses after the initial clause. Scribe 3’s came could also be read as come (the a looks somewhat like an o), which probably led Oliver Cowdery to accidentally replace the past-tense form came with the infinitive form come when he copied from 𝓞 into 𝓟. It is also possible that Oliver expected “the Holy Ghost come down out of heaven” to be conjoined with the preceding complement clause (“the heavens open”). In other words, his change reconstructs the implicit structure of the sentence:
I beheld the heavens open
and [I also beheld] the Holy Ghost come down out of heaven
The bracketed text fills in the intended ellipsis of words.
This change was of course inconsistent with the following “and abode upon him”. In the 1907 LDS vest-pocket edition, the contradiction in tense was removed by restoring came. On the other hand, the 1920 LDS edition eliminated the inconsistency by changing abode to abide, so that now all three clauses are treated as conjoined complements of the verb behold:
I beheld the heavens open
and [I also beheld] the Holy Ghost come down out of heaven and [I also beheld the Holy Ghost] abide upon him
The text does not typically conjoin clause complements after the past-tense verb form beheld.
Instead, in every instance (four more of them) a separate independent clause follows:
Thus there is nothing incorrect or unusual about the original text in 1 Nephi 11:27. (For discussion regarding one other case, which turns out not to be an example of this construction, see 3 Nephi 17:5.)
Summary: Follow the past-tense readings of the original manuscript in 1 Nephi 11:27 (“and the Holy Ghost came down out of heaven and abode upon him”).