Oil loss due to oil filling cap at 2.5 DTI

Hello forum friends, I have a busy day behind me and need your opinion: this morning I drive on the highway, suddenly the message in the BC: engine oil stand check. I drive out, open the hood: everything full with engine oil, filling lid away. My first thought was that I forgot the lid at the last refill (peellich!!).The ADAC comes, takes me huckpack to the next workshop, because he advises me because of fire danger, the ride (of course with more oil) after a motor car The workshop fills up the oil, washes the engine, puts a new original filling lid on it and makes a short test drive. The mechanic comes back, opens the hood: the same again, lid almost unscathed and everything with oil. Great discussion where the pressure comes from. After some consideration together with the workshop master I come to the decision to complete the approx. 50 km home with a lightly drawn oil measuring rod and without much power requirement. r Motor runs clean and round, no white or black smoke, (cooling water and oil look normal) and if I had wanted it would have been tracked off as usual, so was my impression. My long-standing car mechanic at home (free workshop, proven competence for many years) thought it could be due to an added or frozen crankcase ventilation, piston ring breakage or defective cylinder head seal would be unlikely, since the engine runs well, he can tell me more only tomorrow. Wss you mean, what I have to expect, or what can I add to the possible discussion tomorrow. I hope, of course, that everything will go smoothly. Say what you think about it. Thank you so much and have a nice evening!!