This is hard to follow because it looks like you’re confusing downstream and upstream in several of your paragraphs…I think I got the gist of it though, but I don’t see how it applies to the change you’re referring to.
The BOLTs change only says that the preimage must be relayed upstream as soon as it’s obtained downstream. At that point we only specify that nodes should correctly extract preimages from downstream and send update_fulfill_htlc upstream. This doesn’t change the requirements of whether the node should force-close upstream (if its update_fulfill_htlc is not acked) or not.