Avoid Empty Selection in Locking Conflicts

Hi Experts.

I have a planning application built on IP.

The Planing is done at an ID level where users can plan against these IDs.

I mark this ID field in Lock characteristics(RSPLSE) as relevant for locking.

So far so good. I created a copy planing function where in the filter I'm passing only the IDs that were not locked  (out of planning).

However, before this filter and planning function is executed, the PF checks the lock characteristics and found empty selection (_EMPTY_SELECTION_) in locking conflicts and the copy PF fails.

My question is, even after the lock characteristics is specified explicitly, why it shows empty selection issue?

How to avoid this error

Br, Harish