Reducing the size to 20000x10000 works for me, I see none of the artefacts, see attached stitched output. This is a good workaround if you want to carry on shooting at this resolution.
enblend has known bugs related to the memory cache which are responsible for the horizontal lines and presumably the other problems you see. You can workaround the cache problems by disabling it with the -b and -m parameters, though other people have more experience of this than me.
Reducing the size to 20000x10000 works for me, I see none of the artefacts, see attached stitched output. This is a good workaround if you want to carry on shooting at this resolution.
enblend has known bugs related to the memory cache which are responsible for the horizontal lines and presumably the other problems you see. You can workaround the cache problems by disabling it with the -b and -m parameters, though other people have more experience of this than me.