No wan access using back to home

Only to understand, by "automatically detected interface list function" you mean "detect internet"?
This latter Is a know trouble-maker, and It Is generally advised to not use It.
Actually It Is Rule #5, as It may disrupt the working of a router in some subtle ways in many configurations whenever there Is a non-simple or uncommon WAN or tunnel connection (not only in relation to IPv6):
The twelve Rules of Mikrotik Club