The IPW is not updating from the source when the target part geometry is different in the second setup assembly or the part geometry is not defined.
The part containing the source for the IPW doesn't reference the same component for Part Geometry as the work part.
Solution
Change the "Positioning Type" for both the source and the local IPW to "CSYS".
LOCAL IPW Dialog Box
IPW Source Dialog Box
Notes and References
Reference documentation
https://docs.plm.automation.siemens.com/tdoc/nx/1872/nx_help/#search:page=1;rpp=10;query=transfer%20IPW
Hardware/Software Configuration
Platform: all
OS: n/a
OS Version: n/a
Product: NX
Application: CAM
Version: V1872
Function: ZLEVEL_MILL
Ref: 002-8014865