[UVM] CONFIG DB

Hello! I have some question about using config_db. I used predefined uvm function check_config_usage() to compare number of writes be equal to reads.
So when I write something that have enum typedef = int 0, i didn’t receive warnings about not one read it. Nevertheless if i used another variable to set from that enum that coded not as zero, i get info that no one read that variable. It should be?

UVM_INFO @ 97231.000 ns: uvm_test_top.tb [CFGNRD] ::: The following resources have at least one write and no reads :::
test_var [/^uvm_test_top.tb.test$/] : (int) 1