So here we have a common issue on a BMW 5 series E60.
Most people either replace the wrong part or misaligned clock spring.
The 3 tabs on the clock spring
line up to the corresponding tabs in the SZL
When clock spring is not lined up, the SZL will fail calibrations.
You will also notice sporadic steering angle values when monitoring.
Trick is to line up clock spring with SZL slip ring.