I have been trying to get the bottom of this problem, any help would be greatly appreciated @emmanuel.
Sometimes, but not always, when certain conditional logic for visibility is set for groups within my reusable popup, it makes the reusable popup not show on the first ‘show an element’ action; Instead it shows an empty grayout screen. On the second click the popup shows as expected. I have managed to trace this issue to something to do with referencing state logic.
When the reusable popup has a state that is reference used for navigation between pages in the element (this states default is set to something, groups within the reusable popup are visible or hidden dependant on this state, button next increase the state etc) it creates the problem described, but not always! Very confusing.
Below are two video links that show this problem happening and how the states / visibility conditional logic is triggering the issue.