Hyphen is being replaced by $'\342\200\224...' in bash
You're using —, which is an em-dash, instead of a hyphen (-) in the script. With non-proportional fonts such as Terminal (or code formatting on websites) this is hard to see; in regular text, it's more obvious: — vs. -
According to this page, the UTF-8 encoding of an em-dash is 0xE2 0x80 0x94, and when you convert that to octal you get 342 200 224, which are the numbers you see in your output. (Somebody with more bash knowledge than me can explain why this happens.)
Hyphens often automatically get converted to other kind of dashes (on macOS, iOS as well on Windows) which is helpful for the majority of people using computers, but unfortunately not for programmers or system administrators ...