Someone else may have more specific information, but I believe the "chime" will sound if a seat back is unlatched or if the top is not fully latched in the open or closed position. I think in both of these cases the chime doesn't sound unless the car is moving. I recall this happening when I moved my car a little while operaing the top.

If you stop while the car is 'twisted' does the chime stop and then resume as the car starts moving again? This would be a clue...

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