Swipe Widget not showing leading or trailing layers

[masslc]

We reference a map in our Experience Builder and use the swipe widget to select leading and trailing layers. Each time we update our map with a new layer, we update the corresponding layers in the swipe widget's customize settings to include the most recent ones added.

Under Customize settings, I go to select my layers, but it shows 0 Selected, with no layers visible in either dropdown. Randomly, it will work and this won't be an issue which makes us think it is a bug, but does anyone else have this problem? And if so, is there a trick to get the layers to show?

To confirm, the web map is displaying the layers, and the unsaved, updated Experience Builder page, still has the swipe capability working with the previous added layers. 

[TianWen]

Would you provide a sample app or screen recording so we can further investigate it? Thank you!