Floating error json_encode(): Invalid UTF-8 sequence in argument when passing argument via ajax (Yii2 framework)?

Question

JavaScript

Hello.
Framework Yii2. I pass the argument via Ajax (dataType: json) to the getcn action of the main controller.

I came across a strange error:

$.ajax({
   url: '?r=main/getcn&objectclass=' + objectclass,
   dataType: "json",
   success: function(data) {
      $('#test').text(data.result);
   }            
});

values ​​of the form are passed to the objectclass variable : 7017-00-330 7017-01-386 7017-01-989 7017-02-109 For some unknown reason, most of the values ​​generate an error: json_encode(): Invalid UTF-8 sequence in argument , the rest are transmitted normally. For example, 7017-01-267, 7017-00-724, 7017-00-414, 7017-00-324, 7017-00-421 are transmitted without error. A 7017-00-330, 7017-01-386, 7017-01-989, 7017-02-109, 7017-00-212 with the above error. What is mysticism?