Open in new tabs (in a new page) opens only one tab

Steps to reproduce:

1. First, ensure you have a bookmark folder containing more than one bookmark.
2. File → New Window
3. View → Show Bookmarks Sidebar
4. Two-finger-click on the bookmark folder → Open in New Tabs
5. Result: Only one tab created, usually with the last bookmark in the folder. Same result on a new profile.

If I just do this in my main window already containing open tabs, skipping step2, all tabs open. Also, just selecting Open in New Window works as expected.

Expected behavior:

Several tabs created, each one opening one of the bookmarks in the folder (this is what used to happen, one or two RCs ago)

Orion, OS version; hardware type:

Orion version 0.99.124.4.3-rc, macOS Ventura 13.4.1, MacBook Pro 13 in M1 2020.