The bug of windows action center not recognising avast isn't going to cause any harm as such.
The problem is that the action center is going to bug you constantly that you don't have an AV installed or is disabled, etc. That not doubt is why it is set to "on virus protection, it show currently not monitored" to stop the constant notifications; now that isn't a default setting, so someone must have changed that ?
So because you have it set to "on virus protection, it show currently not monitored" should avast ever be stopped/paused/disabled then the action center wouldn't notify you, so you have to monitor it yourself. Fortunately avast makes that a bit easier for you, if part of avast isn't running or is out of date there will be a yellow ! exclamation mark in a triangle over the avast tray icon. If all of avast isn't running or a critical element isn't running there will be a Red X over the avast tray icon and a bigger warning in the avastUI, Summary screen.