The children of tree are not displayed [PLEASE HELP]

I created tree model with one textfield and added test item. After that i added test1 as a child of test item but it doesn`t display anywhere, but i can find it by search.

Api response looks like this

[{
"Example text":"test",
"_pid":null,
"_o":0,
"_modified":1671355214,
"_mby":"6a2edb723839394987000207",
"_created":1671355206,
"_state":1,
"_cby":"6a2edb723839394987000207",
"_id":"6d55808e3464648b2f000334",
"children":[],
"_children":2
}]

So, it shows that item has two children, but “children” field is empty.
Can you help me please with this issue.

This affects me also.

which api endpoint did you use?