In the original text in 1 Nephi 16:28, the complex subject “the pointers which were in the ball” is first given without its predicate, then it is restated using the pronominal form of the subject, followed by the predicate (thus “they did work according to the faith …”). As a result, the subordinate conjunction that occurs twice: before the complex subject and before the pronominal subject.
This kind of repetitive construction occurs in spoken English and is used to help the listener understand a complex subject followed by a long predicate. As a result of the influence of Latinate literary style, such repetition of the subject has been avoided in written English for the past several centuries. Thus the 1830 typesetter deleted the first that after beheld and made the original complex subject the direct object of the verb beheld. (Later, in his editing of 𝓟 for the 1837 edition, Joseph Smith crossed out that same that, thus making 𝓟 agree with the 1830 reading.) As a consequence of this editing, the following that-clause became an additive clause rather than the immediate clausal complement of the verb beheld. For more examples of the repeated subject, see subject repetition in volume 3. The critical text will, of course, restore such usage when it is supported by the earliest textual sources.
Summary: Restore the subordinate conjunction that in 1 Nephi 16:28, thereby restoring the repeated subject for this passage; this kind of syntax is found in spoken English but is avoided in written English.