3 Nephi (LDS 23:14) (RLDS 11:1) And now it came to pass that when Jesus had expounded all the scriptures in one, which they had written, he commanded them that they should teach the things which he had expounded unto them.
Current LDS leaders doubt the teachings of past LDS leaders all the time. In addition to doubting the past teachings, more current LDS leaders have even renounced doctrines that were stated to be from God.