I have read that there were controversies surrounding the persons of the seers Melanie Calvat (La Salette) and Mariette Beco (Banneaux). Both apparitions have full approval of the Church. Calvat is alleged by some to have altered her the messages she received as well as having a difficult personality and Beco lived in co-habitation with a man she was not married to for many years.
I'm not going to include Sister Lucia Santos because I believe she was replaced by a communist infiltraitor.