One of our customers is using BF532 0.5 for power meters. There is a phenomenon I never heard. After static electricity test (10KV), some of the boards will work slower than before. The PLL_DIV, PLL_CTL, and VR_CTL registers will become default values. However, all the other registers are still normal values. And the program will keep running as usual. The only difference is the clock rate and voltage change. Under this situation, these 3 registers will never be modified no matter how many times they were written with different values.
Does any body encountered similar issue? How to recover the system from this fault?