I was not aware there WAS an s2 topic! Am getting balancing info on the Legacy screen, for sure, but have never looked for an s2 message via MQTT. Right now the clouds are out and I've got negative charging going on, so I don't know if I'll have an opportunity to look at this on my system until tomorrow. There IS code looking for s2 in the main.cpp on Github:
else if(uartEvent == "s2") //this guarantees the variable is stored in the varStore so we can get it
auto s2array = varStore.getVar("s2");
if(s_mq_enabled && data_s2_enabled) mqtt.publish((s_mq_prefix + "s2").c_str(), s2array.c_str());
But it doesn't use the same publish steps as the main /sbms topic. Maybe it was never fully implemented??