Follow the logic, the templ->height (acquired via getblocktemplate rpc is more recent than coind->height by 5+ blocks.

https://github.com/LBRYFoundation/pool/blob/next/stratum/coind_template.cpp#L550-L563

	int height = coind->height;
	coind->height = templ->height-1;

	if(height > coind->height)
	{
		stratumlog("%s went from %d to %d\n", coind->name, height, coind->height);
	//	coind->auto_ready = false;
	}

	if(height < coind->height && !coind->newblock)
	{
		if(coind->auto_ready && coind->notreportingcounter++ > 5)
			stratumlog("%s %d not reporting\n", coind->name, coind->height);
	}

yiimp learns block height / update by two ways:

1. actively calling lbcd rpc, such as getinfo, getblocktemplate, etc
2. notified by a stratum message mining.block_update
   In our case, the lbcblocknotify acts as a bridge, which subscribes to lbcd's blockupdate websocket message, and send mining.update_block message to stratum server.

We decided to investigate the 2) route first, and it turned out to be the root cause.

https://github.com/LBRYFoundation/pool/blob/next/stratum/client.cpp#L306-L307

	int coinid = json_params->u.array.values[1]->u.integer;
	if(!coinid) return false;

The stratum server silently rejects the mimg.block_update messages from the lbcdblocknotify bridge.
As the coinid field was reported as string"1425" instead of integer 1425 .