Steps to reproduce the problem:

there are some letters which are exactly look alike, I don't know if they're allowed or not but if they're allowed then we've got a serious problem over here. Why because Nowadays, There's trend of buying/selling Crypto-Currencies and people are spending over thousands of dollar on it. Many of the crypto-currency websites have suspended new registrations, hence, scammers are using these tricks to copy the top websites. 

For example: 

-) “ṇ” (U+1E47) --> https://www.xn--biace-4l1bb.com/ ( http://biṇaṇce.com ) 

note the . under n

Real: https://www.binance.com/

What went wrong?
It doesn't covert it into punnycode.