Active USB device port powers USB-to-UART bridge (CP2102). The logic +3.3V MK26FN2M0VMD18 supply is OFF. CP2102 UART TXD and RXD are connected to MK26FN2M0VMD18 PTE1 and PTE0 respectively. UART TXD logic HI output is partially (1.6V) powering +3.3V supply through MK26FN2M0VMD18 PTE1 (ADC1_SE5a). Data sheet states there are no ESD diodes to VDD on any MK26FN2M0VMD18 digital IO or analog input. Why is +3.3V logic supply 1.6V when it is OFF?