Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32l5/STM32L552/EXTI/FPR2#0x0
EXTI falling edge pending register
FPIF35
FPIF36
FPIF37
FPIF38
https://github.com/modm-io/cmsis-svd-stm32