Cannot save collapsed tags infomation in some case

Hi,
I'm using contao 2.9.5 with catalog 2.0. I created a 3-level taxonomy and then created a tag field using that taxonomy in my own catalog.
When I checked a child item in catalog editing ,then collapse the parent item, and save. Then edit this field again without expanding the parent item and save, then selected child item is lost.
How can I solve this problem? I'm not sure this problem is from catalog or the tabtree
Here is the short GIF video demo:
[attachment=0:1plrwa23]test2.gif[/attachment:1plrwa23]