When connecting the J18 in 2-3 position, J427 gives nearly 0V. Which is similar to what was happening when J18 was in 1-2 position, J427 was 0V.
But when I open the J427,
1. VDD_HV_A = 5V for position 1-2 in J18;
2. VDD_HV_A = 3.3 V for posotion 2-3 in J18 (voltage measured from pin 2 of J427).
3. D3 RED LED of RESET_K3 starts glowing for positions 1-2 and 2-3 of J18.
I think the problem is due to the pin 1 of J427.
I didn't understood your second point but, J25 = 5V and J27 = 3.3V meaning LDO1OUT and LDO2OUT are working properly.
Attached image is showing the D3 LED when J427 is in open position.
Thanks