The US electric car manufacturer Tesla is grappling with an internal issue involving tens of thousands of missing coffee cups at its plant in Grünheide just outside Berlin, dpa has learnt. Factory manager André Thierig addressed the matter at a staff meeting on Monday, saying that a total of 65,000 coffee cups have been unaccounted for. He humorously remarked, “Statistically, each of you already has five Ikea coffee cups at home,” referring to a recording of the staff meeting cited by the Handelsblatt business newspaper on Wednesday. Thierig clarified that his comment about the missing cups wa…