I have the same problem... looked at my sealrings this morning and my #1 looked like your #2
(OK.. that sounded funny) ........: ) your #2 cylinder ring.
mine was worn way out and I have good compression.. I am thinking pre- chamber problemo.. being new I'm not sure what the pre chamber does but mine is very sooty. I will follow your post, very similar problem this 240D

bennett