DRS affinity rules are checked every 3 minutes, and vMotion or an event occur based on the DRS configuration.
As a result, in the case of "should" affinity rules, the virtual machine may run on ESXi hosts that violate the affinity rules for up to approximately 3 minutes.
If you need to immediately place it on an ESXi host that adheres to DRS affinity rules, perform a vMotion.