Details
Datum Leader type is not retained for new leader while creating feature control frame with datum leader type
Solution
Before NX10.0, when user creates Feature control frame with datum leader, after placing the symbol, datum type leader is the default leader type available. (due to dialog memory).
But from NX10.0 onwards, Plain leader type is the default leader type available.
From NX10.0 onwards, user can create multiple leaders with a single Datum leader.
https://docs.plm.automation.siemens.com/tdoc/nx/10/whatsnew#uid:xid841112_v1
From NX10.0 onwards, when you select the terminating object for "Datum" leader, under Leader's List group a new leader is committed (due to above enhancements).
But as you can combine only one Datum leader with multiple leaders, so Datum leader type is excluded from the next available leaders list and so it resets to Plain leader type.
So when you place FCF with the Datum leader, as "Plain" is the new committed leader type under Leader's List group, so it is the default leader type available.(due to dialog memory behavior).
Hardware/Software Configuration
Platform: INTEL
OS: window
OS Version: 764
Product: NX
Application: DRAFTING
Version: V1847
Function: ANNOTATION
Ref: 002-8013941