@planedrop Hmm, I think I have stumbled upon the same issue in a different usecase. In my case it actually prevents me from achieving what I intended, so this is a real problem for me.
https://forum.netgate.com/topic/187925/unexpected-phase-2-behaviour-combines-two-p2-to-one-established
It seems the Policy routing engine does not create a normal routing table but rather it does some sort of supernetting on local and remote nets - perhaps to attempt to only have one routeentry instead of a normal route table. But this is both highly problematic in terms of security and functionality.