I'm not sure how similar this is but I tried the same quite a while back with a simple 5x5 nonogram (Picross) and had similar difficulties.

I found not only incorrect 'reasoning' but also even after being explicit about why a certain deduction was not correct the same incorrect deduction would then appear later, and this happened over and over.

Also, there's already a complete database of valid answers at [1], so I'm not sure why the correct answer couldn't just come from that, and the 'reasoning' can be 'We solved this here, look...' ;)

[1] The wonderful https://pixelogic.app/every-5x5-nonogram

> I found not only incorrect 'reasoning' but also even after being explicit about why a certain deduction was not correct the same incorrect deduction would then appear later, and this happened over and over.

Because its in the context window and a lot of training material refers to earlier stuff for later stuff it is trained to bring up that stuff again and again. Even if it is in the window as a negative.