today one guy got rejection from LVO, he was Oct 2016 applicant, his application was with Mississauga from Oct 2016 till Dec 2017. they transferred the file in january 2018 and in one week he received an email that his application is rejected. I talked to him what is reason but he was telling nothing wrong.
There is always something when such harsh decision is made by LVO.
LVO know about cultures of applicants, They know what pictures tells them, they know what expressions are saying in photos, They understand the second marriage is genuine or it is for getting someone to canada only. They understand Nikah ony cases can be true, and also they doubt it to extreme.
there are many things they look into, and they get experience while going through alot of applications of different types. they can make mistakes but that is rarely. and for their mistakes Appeal tribunal is made to address such mistakes.