Jim, the filter was installed correctly.
Handle side up.
The washers were fine on both sides. No obstruction inside.
I don't recall any difficulty in removal. I can only
assume that it went in without incident 3500 miles ago.

Yes, it is intriguing.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD