There are tons of examples…here are a few:
- Joseph Smith practiced polygamy, even with married women
- There never was a revelation that Black people could not hold the priesthood
- Women used to be able to pass the sacrament
- Joseph Smith used a seer stone to aid in translating a large portion of the Book of Mormon
- There are many, many others...
Kids hear about this stuff for the first time from sources other than Church and when they bring it up in a Church setting, they are shot down by adults who don’t know how to deal with the questions…and these kids feel lied too.