you guys have 15 minutes bevore the backpack dissappear after you died. this is working like its supposed to do -
In your OP screenshot the one you have highlighted is what you are 'subscribed' too.
Try going in to the F2 menu & finding the 'Zap-Runabout' & see if any of them have the little man with the small spanner icon & the Update box is selectable.
The little man with the spanner is what you have published on the workshop.