SameInstancePreferenceServiceInstanceListSupplier.selectedServiceInstance(...) not call

[Anton-Bondar]

I use Spring Cloud Load Balancer 3.1.1. And I want to use same instance strategy for it.

spring:
  cloud:
    loadbalancer:
      configurations: same-instance-preference   

But each time even service calling not first time SameInstancePreferenceServiceInstanceListSupplier.previouslyReturnedInstance == null
As I understood following method should set it: SameInstancePreferenceServiceInstanceListSupplier.selectedServiceInstance(...)
But it doesn't call in my case. Please describe how it should works or maybe it's a bug?