IFTE odd behaviour

[BruceH]

Using the PC emulator (2018 10 16 build) in Home:

Code:

IFTE(1,2,3)                2
IFTE({},2,3)               0
IFTE({1},2,3)            {2}

The first is as expected; the second is unexpected but I could live with it; the third is 'interesting'. :-)

Edit: CAS mode using 'when' is nearly as quirky: when({1},2,3) just returns unevaluated which is okay - sort of the CAS saying "I've no idea what you meant here" but if you edit it, the when changes into the ? : form and goes back again when you enter.