If you have a selectable list (that allows more than one selection) and you make multiple selections, then leave the view, then come back - the items you selected will not display.
Even if you correctly set the default items to the list of whatever - it will not work.
I filed a bug and Bubble said this is a known issues. I haven’t seen mention of this bug anywhere - and since I wasted time on a known issue…I’m posting to save you time.