I get a strange error in my oh-my-zsh terminal related to UTF-8 encoding

Question

I am using iterm2, and oh-my-zsh. After updating oh-my-zsh, I get the below error upon every command.

iconv: iconv_open(, -t): Invalid argument
Error converting string from  to UTF-8

The command that I run e.g npm run watch still works, but at the end is this error always.