Tested the problem film back again after removing the masking that found its way into the frame. Good news is the image is cleaned up, bad news is there is still a bit of a light leak.

That being said, not bad overall. Also, tried out Diafine developer this time. It’s a compensating developer (i.e. brings down highlights, brings up shadows) which works well for scanning. The development process itself is also fairly simple (4 minutes Solution A, 4 minutes Solution B) and the developer can be reused (a big plus here). I think more agitation might be needed, although everything I’ve read says “gentle agitation”. There are some images that are streaky, though, which usually means uneven development.