If you have the Bookmarks Toolbar activated with folders created within, the first bookmark entry in each folder cannot be clicked on. Moving the cursor atop the entry does not select it until you read the very bottom of the text. Quite counter-intuitive and annoying.
It seems your issue is related to this thread.
It’s a known bug and already logged here. You can track the progress there. And I added your comment to github issue, too.
At the moment, all I can recommend is make sure you have a tab under the folder you want to open or select the entry from the bottom edge of it.
Hope this can help for now, until the fix is there.