In the case where INTB is connected to VIO through a resistor , the VIO cannot be higher than (VSYS + 0.3V) .
The reason is because in the circuit we have an ESD diode from INTB pin to SYS_A (SYS). And if VIO is higher than (SYS_A (SYS) + 0.3V) it will turn on the ESD diode.
This voltage limitation is stipulated in the datasheet Absolute Maximum Ratings table on page 9:
INTB to GND .........................................-0.3V to VSYS_A + 0.3V