option byte of STM32H743VI was modified abnormal when debug by IAR, and if reset FZ_IWDG_STOP and FZ_IWDG_SDBY to default (1), the MCU can't run normally.

[EXUE.2]

option byte of STM32H743VI was modified abnormal when I debug it by IAR, FZ_IWDG_STOP and FZ_IWDG_SDBY default value is 1, but after modified abnormal, I found the option bytes bits change to 0 except NRST_STOP_D1 bit, and then I try to reset all bits to default, but found when reset FZ_IWDG_STOP and FZ_IWDG_SDBY to default (1),the MCU can't run normally, and after I modified FZ_IWDG_STOP and FZ_IWDG_SDBY to default 0, the MCU can run again.

Do you know why?

default value as below capture:

abnormal modified value as below capture: