A problem probably having common roots with ZBX-15326

Steps to reproduce:

1. Define Template A. Define discovery rule (LLD) in it, named disovery1.
2. Define Template B, create item prototype item1 inside discovery1
3. Export Template B to xml

Result

item1 and discovery1 is not exported

Expected:

This seems to be design flaw and inconsistency.

So, either new item1 in child Template B must be exported to XML or it must be forbidden to to append anything new to discovery rules inherited from parent templates.