Altering an array value in a structure causes the menu to collapse

When making any alteration to an array within a UDS the drop-down menu for the array collapses.

Regression: Yes
Works: 2689999
Broken: 2693272

1. Create a new Blueprint Structure
2. Change the default variable to a String and set as an array
3. Add at least 1 element
4. Give that element a name
5. Click the + icon to add another element

Result: Array drop-down menu collapses. Requiring you to unfold the menu with each addition/change (see .gif attached)