I noticed another weird thing and I can't confirm if this happened earlier:
VWAP with 2 std deviations: I have Binance with BTC/USDT and ETH/USDT loaded. BTC/USDT chart shows the indicator just fine, but the ETH doesn't show it at all, see screenshot:
https://ibb.co/CPhvK2p
It is interesting, there is just nothing on the chart. I think earlier when I was using the Alpha version of Bookmap it used to work fine on all charts at the same time. I tried 3 different versions of your indicator: 2.1.1 ; 2.1.2 and 2.2.1 and it is the same with all - BTC chart shows the indicator, ETH doesn't. My bookmap version is 7.2.0 b19
Let me know if i can provide more info to help debug it
EDIT: just noticed it fires voice alerts on certain levels, it just doesn't draw the lines