Hi @Anonymous,
You are getting this error because your Headers are different. You are using odata=verbose. In my example I was using the odata=nometadata value.
Can you try and use these headers:
{
"Accept": "application/json;odata=nometadata",
"Content-Type": "application/json;odata=nometadata",
"X-HTTP-Method": "MERGE",
"If-Match": "*"
}