1.you may forget still have 10K resistor in the picture
2.After VBAT_SW is powered on, it will turn on Q1 and pull FS26_VDEBUG low to 0V
For OTP mode(Flash MODE), it is necessary.
please take a look at the below two chapters:
Rev.3
Chapter 23 OTP and Debug mode
When the OTP configuration is complete, the fail-safe state machine will start in Debug mode when the voltage at the DEBUG pin is below VNORM_max (NXP recommends applying 0 V or GND).
and Figure 72. OTP mode flowchart until safety outputs release