I have same problem but not every time. I would say that 1/3 times whwn i open WB i get MAF, but not right away.. usally it happens when WB is open long time. Anyways have also get MAFs in game so its not WB problem. This started to happen only few revision ago and i dont use latest MCP. So if its MCP its something from main game what is changed few revs ago and cause problems with MCP.