It seems that json.me forcefully decode everything as UTF-8. String encoded in latin-1 and ucs-2 often decoded as garbled text.
JSON is not expected to be in latin-1 or UCS-2.
The default encoding in the specification is UTF-8.
So if you feed invalid input, don't expect a good result.
So to be safe you should correctly transcode your input before feeding it to org.json.me.