CZ,
Without going into specific settings, I would say that when you ran the Avast Email Wizard during setup, you checked "Protect all future accounts".
If so, Avast will look at any new accounts as yours and report results to you.
To correct this, you will need to manually configure Avast for multiple accounts (even though your wife is a limited account) according to the instructions found in the "Menu" under Help. It really is easy.
Techie