Try to connect Miner DIRECTLY to your main internet Router!!!
Without switch or other secondary device. Directly into your main router.
I dont think that will be de solution.... i have L3+ and D3 connected with switch.... and works perfectly... L3+ / D3 has Cgminer by default.... each time i make IP Report Reset, its works and my internal S9 IP is different, the matter is not the connection
The matter is the BMminer, someone could got another alternative solution than bmminer-cgminer492 "Zwilla" update ?

thanks