Having same issue as well. Even updating with the same values as are returned by API throws an error
“error_code”: “ColumnValueException”,
“status_code”: 400,
“error_message”: “change_column_value invalid value”,
“error_data”: {
“column_value”: “{"url:"=>"http://google.com", "text"=>"test"}”,
“column_type”: “LinkColumn”
}
I could actually send arbitrary property names and they will be written into the field (not displayed though). Text property throws an error regardless of what its content is.