I’m not sure if I’m missing something in this post. The netbalancer is basically a load balancing algorithm to determine how much traffic to send over multiple uplinks.
It uses weights, latency and other user defined preferences to make the decision which uplink to send traffic out.
From your post it sounds to me like the netbalancer is working probably.
How exactly did you intend for it to work? Maybe there was some confusion on how to implement it.