Found some gasket type residue in oil filter - help !!!

[rbizet]

Hello,

I am trying to get some feedback as to what the rubber residue in my oil filter could come from. It is definitely not metallic, it is pliable, has a rubbery feel to it and the color is olive green. It looks like a gasket material.

It started to appear during last oil change 6k ago. My car is a 2000S with about 55k miles and always maintained perfectly.

I thought it might be the AOS but I replaced it and the diaphragm which has the same olive colour was intact.

I was told that when the previous owner had the valve cover resealed maybe they used a green compound but I checked the engine and the gasket material is black.

I am running out of idea where is this coming from?

Please anybody can help?

Thanks in advance