I have seen this happen firsthand. More than once actually.
First time was an s54 (e46 m3 engine). Customer got a CEL and very strange running issues after a track day. Brought it into us and we had a hell of a time figuring out what the issue was, as compression was on low end of the allowable spec. Other than a rough run situation on a cold start. Cold compression was low, but would only slightly increase with oil being put into the cylinders (Wet compression test) . Upon dismantling, catalyst material was found in exhaust PRE-CAT, and what happened was the exhaust valve seats were not sealing properly. I cannot remember at this point whether there was catalyst material in the engine oil or not, but it would seem likely that there was some there.
Second one was on an N55, newer production in an X6. Came in with turbo whine. Removed Cat while replacing turbo to find it badly damaged, further inspection found again, exhaust valve seal wear w/ minor scrubbing/scraping on the cylinder walls, and fine metallic material in engine oil.
It does happen, if I knew why then I would try to explain it better. But
@matreyia is not crazy or getting hosed. IT can and HAS happened.