Weird focus shift issue with Contax T2. Any ideas why?

Shot on Contax T2 that I've been using for years without any issues. First photo is from a roll of Harman Phoenix and around 7 photos from that roll have weird focus shift issues similar to this. Second photo attached is the negative of that photo.

Dev by local lab, scanned by myself using Lumix G9 and macro lens. Other negs I scan turn out fine and I rescanned the Phoenix roll being extra careful with focusing on the grain and aligning the negative/camera using a mirror with the same outcome. So that rules out the scanning process.

I then shot a roll of Fuji 200 and all photos came out fine (example shown in third photo attached) with the expected in and out of focus areas. So it seemed like this problem fixed itself.

Any ideas on why this could have happened?