The 1852 LDS edition replaced the plural abominations with the singular. This reading has persisted in the LDS text. As explained under Helaman 13:17, either number for abomination(s) is possible when conjoined with wickedness, although the plural dominates. In each instance, the critical text will follow the earliest reading, thus the plural abominations here in 4 Nephi 1:39.
Summary: Restore in 4 Nephi 1:39 the plural abominations, the reading of the earliest textual sources.