@Intruder, sadly if any ILS is tuned, even to another airports runway it will prevent the approach mode from activating the non precision approach, only exception of course is the LOC or ILS G/S out approach.
Common mistake is to never retune the NAVs and let them on the ILS of the departure airport and then being puzzled why the plane simply continues straight through the extended centreline without any interception. Not a big issue, one just has to be aware of it. Funny enough, never had that issue with a GBAS channel number, but it is much more rare to use those anyway.