No that is not normal. It won't hurt anything but the WG is not tuned correctly. I went through this with the first few EWGs that I tuned.
I am not familiar with the HOA BCS but if it is a blocking interrupt style like the GM or Perrin, then that doesn't work well with the EWG. You would be better off using the stock bleed style and getting retuned.
Basically, the blocking style BCS uses less duty cycle to control boost and the EWG need less duty cycle also. It is very hard to tune a blocking style BCS for an EWG as a little less duty cycle, and you don't meet boost target. A little more and you get WG flutter (which is the noise you have now). It is too fine of an adjustment.
The blocking style BCS work awesome with IWG though.