Addresses are not wrapping within zeropage as they do on a real 6502.
When running LDA ($FF), Y with Y = 0, the 6502 simulator takes the low byte from $FF and the high byte from $0100.
It can be seen when running this code:

LDA #$00
STA $00

LDA #$02
STA $FF
LDA #$04
STA $0100

LDA #$AC
STA $0402

LDA #$c2
STA $02

LDY #$00
LDA ($FF), Y

After executing this code, A should be equal to C2 and not AC.
PinoBatch, on the Nesdev wiki figured out that it is due to getWord() which does not handle wrapping: