Concretions that meet multiple interfaces, do not share single object unless made manually.

If a concretion meets multiple interfaces that you want to register, it must be done manually now, as using the interface to concrete register results in a per interface object, rather than the expected single shared object.

e,g.

var s = new Service();

.Register(s)
.Register(s)

behaves as expected, anything asking either services interface gets the same object, however.

.Register()
.Register()

makes two instances of Service. This may be desired but should be clarified or perhaps configurable.