Transmission slightly jerks when downshifting from 6th gear to 5th

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Hello, my car is 2013 Audi A8L with 8 speed trans. I’m experiencing a slightly jerkiness when the transmission down shifts from 6th gear to 5th. It is not very forceful and noticeable, but for a ZF 8 speed I know such jerkiness shouldn’t exist. All other gears work fine and 5th to 6th up shifting is also okay. Does this sound like an issue caused by hardware, such as worn out friction clutch plates, or software like TCU programming? Thank you very much!