setColumns problem when dataTree:true and first column field in Tabulator.data is undefined

[RDamman]

Describe the bug
setColumns problem when dataTree:true and first column field in Tabulator.data is undefined. After calling setColumns an error occurs and the Tabulator is in a strange state.

To Reproduce
Start my fiddle and press the button "Change columns"

Expected behaviour
You get the expected behaviour when you change
in var tableColums1
{title:"Name", field:"name2", width:200, editor:"input"},
into:
{title:"Name", field:"name", width:200, editor:"input"},

Desktop:
Browser [latest Chrome and Firefox on Windows 10]

https://jsfiddle.net/nfs8uy4q/14/

<script type="text/javascript" src="https://unpkg.com/tabulator-tables@6.4.0/dist/js/tabulator.js"></script>

.tabulator{
background-color:#f3f3ff;
}

//Sample Data
var tableData = [
{id:1,name:"Bob", n:21, _children:[{id:10,name:"Bob1", n:22},{id:11,name:"Bob1", n:22}]},
{id:2,name:"Steve", n:23, _children:[{id:20,name:"Steve1", n:22},{id:21,name:"Steve1", n:22}]},
{id:3,name:"Jim", n:50},
]

var tableColums1 = [
{title:"ID", field:"id", width:200, visible:false},
{title:"Name", field:"name2", width:200, editor:"input"},
{title:"Amount", field:"n", width:50, editor:"input"},]

var tableColums2 = [
{title:"ID", field:"id", width:200, visible:false},
{title:"Name", field:"name", width:200, editor:"input"},
{title:"Amount", field:"n", width:50, editor:"input"},
]

//Example Table
var table = new Tabulator("#table", {
data:tableData, //load data into table
height:200, //enable the virtual DOM
dataTree:true,
columns:tableColums1
});

function changeColumns()
{
table.setColumns(tableColums2);
}