I would call and ask them if they touched the gearbox. They might have checked fluid, changed the level. They could have updated transmission software.

You can check fluid level. The transmission needs to be at temperature, engine running.

I would keep the log, and ensure that the problem is noted by the dealer on a work order prior to the warranty expiring. Worst case, if it fails after the warranty expires, you will have a history and so can claim it as a failure during the warranty period.

Good luck with it.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue