After consulting with a different Hyundai service manager (recently factory trained), we agreed it is a drive-by-wire problem. Requested a new computer card (I offered to pay for the card w/o warranty assistance) and found it is keyed to the vehicle ID number. Replacing the card or updating firmware is not possible on this model.

Car lurches dangerously when first engaging in Drive. Scares the heck out of driver. Could hit another car before it finally evens out. Dealer cannot find the problem and at this point refuses to do anything about it even though it is a safety issue. Manufacturer also refuses to provide any assistance--so much for quality control at Hyundai.