The German Federal Motor Vehicle Transport Authority did not provide any reasons for the new investigation and only noted that this specific function of Tesla's autopilot and full self-driving technology may not be permitted in Europe.
https://www.notebookcheck.net/The-auto-lane-change-function-that-is-part-of-Tesla-s-full-self-driving-capability-may-be-declared-illegal-in-Europe.602275.0.html