Different behavior for lists and individual elements

When creating the queries of editors, it is useful to work with a list of elements, to quickly test different cases. E.g. Signal has Source, Signal does not have Source.

This looks like this:
GET (!Signal/source&TRMn0;n0@PARENT/inputs/declaration)
which triggers this error: EOQ_ERROR_UNKNOWN(9): Unknown error type u4: Segment 6 (PTH): NON has no feature declaration
From my understanding, this should work, since TRM handles the no-source case.

Individually, it works:
GET (!Signal:l30/source&TRMn0;n0@PARENT/inputs*/declaration) -> n0
GET (!Signal:l29/source&TRMn0;n0@PARENT/inputs/declaration) -> [(#y5696)]

Since the editor is querying every Signal individually, this is no problem in XGEE. However, during development, this would be handy.
This is a compressed example, real query: GET (!SignalAssignment/signal&TRMn0;n0/targets*{(@PARENT/task_opp_TaskAssignment*/device&ANY(#u5992))))