We has a visit from our TAS a couple of weeks ago, along with a couple of other engineers.
I posed the question to them, and although there hasn't been confirmation, the feeling (assumption) at the moment is that DRS does reassess rules soon after HA has completed its actions.
On the matter of "das.respectVmVmAntiAffinityRules" and "das.respectVmHostSoftAffinityRules" these are now set to "true" by default, and more disconcertingly HA can break these rules still anyway, and probably always could. Information here VMware Technical Partner Roundtable: Where’s the HA enforce VM-Host and Affinity rules option in vSphere 6.5? This came up in my other discussion Where is "das.respectVmHostSoftAffinityRules" documented?