This anomaly applies to IC Rev. Engineering C, build codes CKAA-CA0, QIAA-CA0.
LFRC oscillator frequency is wrong after calibration, exceeding 500 ppm.
On some devices, when entering System ON Idle while calibration is ongoing.
After calibration, LFRC has a frequency offset that is outside specification.
*(volatile uint32_t *)0x40000C34 = 0x00000002;
Apply the following code after the RCOSC32K calibration is finished:
*(volatile uint32_t *)0x40000C34 = 0x00000000;
This workaround is included in SDK v15.0.0 and SoftDevices S140, S132, and S112 v6.0.0.