In reply to Reuben:
Ok.
Can you also see (and post it here as well)output of
$display("Sequence hierarchy: %s", get_full_name());
in your sequence while using ‘null’ in place of sequencer.
Another thought is, setting configuration in test with
uvm_config_db#(testbench_env_config)::set(this, "*", "cfg", cfg);
makes configuration visible from test to downward hierarchy. But, the sequence is part of uvm_top/uvm_root where config visibility is not there. e.g. uvm_top.sequence_h