Bookmarks not remembered after restart

If I set a bookmark on a conference room, a new menu item (bookmarks) appears containing the option to open the conference room. However, if I exit Spark and start it again, all bookmarks and the menu item are gone.

I’m using Spark 2.6.3 on Windows 7 and installed it using the defaults.

Is this a known bug? Is there a workaround? I couldn’t find anything in the issues.