Dragging a Favorites folder from the Bookmarks menu into itself in the Start Page consistently crashes Orion

Steps to reproduce the issue:

1. Create a Favorites folder in the Bookmarks window Bookmarks -> Show Bookmarks
2. Add at least one item into the folder
3. Open a new tab with the start page visible
4. Drag the folder from the bookmarks window into itself on the start page
5. Orion now crashes

Video of the issue:

Expected behavior:
Attempting to move a folder into itself should neatly fail instead of crashing Orion.

Orion and macOS versions:

Version 0.99.129.1-rc (WebKit 621.1.2.111.4)

Sequoia (15)