The BMW dealer checked with the technical support and confirmed there is a case in the system for this plug. The mechanic was annoyed that they didn't get this info to him, although he has an ongoing case, and he had to learn the info from me and had to ask the support. So for now BMW hasn't made a recall and is keeping a tight lip about it. However in a few weeks they will service it and do whatever they have to do. So for anyone having the mystery oil level issue be more persistent and they will yield eventually. The same as with the cold start issue.