Id get the person who over tightened to fix..
There are some seals out there that are too hard..
Choice is yours new seal or filter..
If it was ne doing it myself ? I would try seal first..
BUT I would carry a spare filter..
I do agree with you however we have traveled just over 2000 k, and only noticed the weep after 1000 clicks. Could not trace it to be a pipe connection or what. Went back to garage when we got home and left it for a day and then brought it home. A FEW DRIVES OF 20 K and seamed ok. Sat for 3 weeks over christmass and started it up on NEW YEARS DAY AND LET IT RUN FOR 10 TO 15 MINUTS only to have that lovely small of diesel in the morning.
We will not be using it for a month so we have plenty of time to argue (he said shee said)