Lock up state in ARM Cortex M4F

Hello community ! 

I hope you guys are doing fine, this is my first post here with the arm community. 

I have a problem regarding my MCU Arm Cortex M4F S32K144, after performing several resets each 3/4 seconds (needed for my test), I see that, randomly, the arm enters a LOCK UP state after the 60th, 77th, 144th... reset attempt, at a random occurrence each time I run the test (the test basically performs a hardware reset to the arm). 

I could detect that my MCU enters a Lock by reading the SSRS register, it states that the arm has entered the LOCK UP state. 

Do you guys have any idea which registers I can read in order to tighten the researches regarding the causes that led the MCU to go to the LOCK UP state.

Best regards !