One wonders here if the original text, perhaps even the original manuscript (which is not extant here) read “I had requested it of my Father which is in heaven”—that is, the relative clause read in the present tense rather than the past tense. Perhaps the surrounding past-tense verb forms (“was pleasing … had requested … had heard”) led Oliver Cowdery to accidentally write down “was in heaven” or Joseph Smith to accidentally dictate “was in heaven”.
The synoptic Gospels have 18 examples of the be verb being used to link the subject Father with in heaven—and in all 18 cases, the verb is in the present tense (as in the Lord’s prayer: “Our Father which art in heaven”). Yet all 18 of these cases are surrounded by verbs in the present tense, not the past tense. Seven of these present-tense instances are in the Sermon on the Mount and are therefore cited in 3 Nephi. In each of these seven Book of Mormon cases, the presenttense forms prevail.
It is possible that the use of the past-tense was in Jacob 7:22 may actually be intentional. As a related phenomenon, consider that aspect of English syntax which allows past-tense forms in indirect quotes even if the meaning has shifted from the past to the present or future, as in sentences like “I told him that I was coming next week”. Here the subordinate that-clause takes the tense of its main clause, even if it is semantically wrong. The Book of Mormon text seems to allow a related kind of tense backshifting for relative clauses in a past-tense context, as in the following example found earlier in this same book:
It seems that in both Jacob 4:5 and Jacob 7:22 the text intentionally maintains the past tense even when there has been a semantic shift to the present in a relative clause. In fact, in both cases the text refers to two facts that are eternally true: namely, the Father is in heaven and Abraham’s offering up of Isaac is a symbol of God offering up his Son. But the preceding past-tense verb forms allow for a shift in the overt tense from the present to the past in the following relative clause. Since this kind of tense backshifting could be intentional, the critical text will allow it here in Jacob 7:22 as well as in Jacob 4:5.
Summary: Maintain in Jacob 7:22 the past-tense was in the relative clause “which was in heaven”; although the phrase “my Father which is in heaven” is normal, the preceding use of the past tense seems to permit the past tense to be extended into the following relative clause; there is a similar example of this tense backshifting in Jacob 4:5.