2003 BMW 325 RE: White smoke from the hood/burning rubber s

I recently went away and parked the car in the garage for 10 days. When I drove the car on the 11th day I noticed some smoke coming from the hood and it smelt like rubber burning. I checked the pin and it was level, no car lights came on and there were no oil leaks. (I also checked to see if a grocery bag got caught under neath)

To be safe I took it into a local mechanic and they told me that if the needle is level and there is no leaks there is nothing to worry about and perhaps some moisture came into the valves which caused the smoke. I drove the car after for a couple of days with no issue.

Over the weekend I had the car parked in the garage. I took the car out after 2 days parked for about 20 min. And when I returned I parked the car in the garage and I noticed some smoke coming from the hood and the smell of burning rubber. I did all the above checks and saw nothing unusual. Its obviously something. Can you help?