&2 &1 is in the SAP namespace

What causes this issue?

&V2& &V1& are in the customer name space.

How to fix this error?

The names of your own objects should begin with <ZK>Y</> or <ZK>Z</>.
Objects that do not begin with <ZK>Y</> or <ZK>Z</> are part of
the standard
objects and should not be changed. All changes to these kinds of objects
are considered to be modifications and will be overwritten during the
next upgrade.

Error message extract from SAP system. Copyright SAP SE.