I replaced the primary monitor with a new one and now most of the shortcuts on the secondary taskbar are gone. The ones still there are for apps, the ones that are gone were for vbs scripts that start ffplay to display rtsp camera feeds. I think it's because DF used to call the secondary display #1 for some reason, and now it is #2. I went through some monitor numbering problem before but I can't remember how I fixed it, or find the discussion thread.

Fixed it by following instructions here: https://www.displayfusion.com/Discussions/View/how-to-recover-taskbar-and-window-location-settings-after-updating-to-displayfusion-34/?ID=7843e9c5-e616-42cc-977c-39c144a7798a

Needless to say I backed-up the DF settings and the registry keys before I did this, then I restarted DF and everything was back.