I have the same issue as @rekameohs in version 101.0.4843.43.
I have noted that the length varies. When a top-level bookmark folder only contains folders with the longest description being "Security & Privacy", the descriptions are truncated to 15 characters eg "Security & Priv...".
Adding/editing a bookmark with a longer description (30+ characters) increases the number of characters shown.
The issue is obviously caused by the value set as the truncation threshold being too low.
As proof, creating a new folder with bookmarks named "A", "B" etc fails to show any characters.