I'm developing an application based on STM32L4 on a custom board. Program is running fine but I noticed that sometimes (maybe once after four days working) device is reseted. In order to find the reason of this reset, I removed watchdog and waited for the reset to happen again: after some days perfectly working, I have noticed a reset (device stopped and showing status through some LEDs) and status LEDs tell me that the reason is 'BusFault' because device has stopped in the 'BusFault_Handler'.
Which could be the reason of such error?
Which is the best way to find the reason of such behaviour?