Reproducing Steps:

1. Open the attached xlsx file in ZSS App
2. Change focus to "B1"
-> data validation dropdown contains "Item 1" through "Item 5"
3. Select any value from the dropdown list
4. Change focus to "B2"
-> data validation dropdown is empty

Both data validation dropdown lists are working when opened in Excel.

Data validation source formulas:

B1: =Current_List
B2: =INDIRECT(SUBSTITUTE(B$1, " ", "_"))

Named Ranges:

A8 : E8 -> Current_List
A9 : A13 -> Item_1
B9 : B11 -> Item_2
C9 : C9 -> Item_3
D9 : D10 -> Item_4
E9 : E12 -> Item_5