E 320 Bluetec Oil Cooler Problem

[nyko46]

On March 2022 I found a oil leak on my 2008 Mercedes Benz E 320 Bluetec
and found it was from the oil cooler inside the V of the engine block.
The car was sent to a certified Mercedes Benz mechanic which had the issued resolved using OEM parts. The mechanic gave me a warranty of 12 Months or 18000 Miles. At the time of the repair the car had 144490 K Miles and now, 02/2025 the car has 155290 K Miles totaling 10800 K Miles after repaired.
As I retired, the car is 95 % of the time on my garage, not in use.
The question is: Is it supposed these oil seal to go bad so quickly (10800 Miles) as happened with mine?
I know that the parts used are OEM parts including a new set of all o-rings to re-assemble all parts taken apart to reach the oil cooler.
Are there any suggestion about this issues?
Thanks