Swiss pension and QNUPS

I am dealing with an estate in which the deceased had worked in Switzerland. He had left Switzerland a few months before the pandemic hit. He had a swiss pension established with a well known worldwide insurance company. In Switzerland, when an individual leaves their employment without instructing the insurance co as to how the vested benefits are to be used, the benefits are transferred to an institution called Stiftung Auffangeinrichtung (SA). The SA open an account in the name of the insured person for the vested benefits transferred to it. The funds are held by the SA until the insured instructs them to be transferred to a new pension scheme. The insured can request cash payment if they permanently leave Switzerland. In the event of death without nomination the benefit is paid to a family member (in this case, a parent).

I am currently completing IHT400 and in particular IHT409. On answering the questions in boxes 8 -16 it seems the result is that the funds form part of the estate (and are thus taxable for IHT).

Does anybody have any experience of anything similar? I have been considering QNUPS but the fact the funds had already been transferred away from the insurance company to the SA would seem to preclude this.