In my application, EXTI is used for external signal triggerring. In STM32CubeMX generated codes, MX_GPIO_Init() initializes GPIO & EXTI related stuff but without enabling SYSCFG clock, in which case the EXTI is not functional.
I think as I selected pins as EXTI in GUI of STM32CubeMX, the generator should enable SYSCFG clock automatically otherwise the function of generated code is not complete.
I also noticed that STM32CubeMX 4.26 has been released. I have not tried the lastest version and I don't know if this problem is fixed.