Hey,
Sorry it still doesnt work for me, also I found another problem.
Here are screenshots of what is going on,
The child named "D" is lazy loaded:

After typing "D" in the filter all the data is gone:

Also,
Typing "B" in the filter, then opening and closing a few times the node "B" (No child is loaded because he has only
one child named "D" and the filter is "B") :

Then remove filter, and "D" is duplicated:
