PauliExpectation warning given unexpectedly

[woodsp-ibm]

When running the following test

https://github.com/Qiskit/qiskit-nature/blob/01ec334a18fbcf2368765dfd2d522e116da9de0e/test/algorithms/ground_state_solvers/test_groundstate_eigensolver.py#L334

it prints this message unexpectedly to me.

Measured Observable is not composed of only Paulis, converting to Pauli representation, which can be expensive.

In looking it seems to be when the expectation is taken of the aux_operators. This is a ListOp of PauliSumOps i.e. a List of a number of different operators like dipole X, num particles etc of which an expectation is computed against the result state of VQE to measure these.

Now at the time of writing this test is failing to meet the final result. That's a different problem than the above but in looking at that is when I saw this message appearing