So my setup  is like that:

MODEM (aka router with PPPoE Passtrough) - ROUTER (handles EVERYTHING except wifi) - SWITCH (for all ethernets in my house) - DECO MAIN (ethernet) DECO 2(ethernet) -DECO 3 (wifi)

its always the one that needs to work with wifi, that even after reset, switching nodes etc starts blinking red  1min after install. Even if its next to the main.

Btw what features do i loose using AP Mode, except Parental Control, Antivirus UPNP etcetc, do i loose Powerline/mesh, can the deco still cover as  much as with router mode?

Not using router mode as double natting, but if i use it, with main deco ethernet and the others wifi it works perfectly fine..