It is not a new rule. Already existed back in 2011. However, it only applies for those with annual income of RM 36k and below, they cannot have more than two issuing banks' cards. For e.g., you can have few HLB cards and few UOB cards even below RM 36k, because still two issuing banks, not two cards actually.

There are many factors which affect the credit card application actually, not only because of income.
Have you tried checking your CCRIS especially if you have PTPTN?

Maybe your commitment is too high vs income? Not sure. First step, to check out your CCRIS score.

Easiest is to go to Bank Negara as it is a kiosk, you just need to insert your MyKad and scan thumbprint then you will get it instantly. Else, you can request. http://creditbureau.bnm.gov.my/reportobtain.html